83_FR_26030 83 FR 25922 - Air Plan Approval; New Hampshire; Nonattainment Plan for the Central New Hampshire Sulfur Dioxide Nonattainment Area

83 FR 25922 - Air Plan Approval; New Hampshire; Nonattainment Plan for the Central New Hampshire Sulfur Dioxide Nonattainment Area

ENVIRONMENTAL PROTECTION AGENCY

Federal Register Volume 83, Issue 108 (June 5, 2018)

Page Range25922-25936
FR Document2018-11597

The Environmental Protection Agency (EPA) is approving the State Implementation Plan (SIP) revision that the State of New Hampshire submitted to EPA on January 31, 2017, for attaining the 1- hour sulfur dioxide (SO<INF>2</INF>) primary national ambient air quality standard (NAAQS) for the Central New Hampshire Nonattainment Area. This plan (herein called a ``nonattainment plan'') includes New Hampshire's attainment demonstration and other elements required under the Clean Air Act (CAA). In addition to an attainment demonstration, the nonattainment plan addresses the requirements for meeting reasonable further progress (RFP) toward attainment of the NAAQS, implementation of reasonably available control measures and reasonably available control technology (RACM/RACT), base-year and projection-year emission inventories, enforceable emissions limitations and control measures, and contingency measures. EPA concludes that New Hampshire has appropriately demonstrated that the nonattainment plan provisions provide for attainment of the 2010 1-hour primary SO<INF>2</INF> NAAQS in the Central New Hampshire Nonattainment Area by the applicable attainment date and that the nonattainment plan meets the other applicable requirements under the CAA. This action is being taken in accordance with the CAA.

Federal Register, Volume 83 Issue 108 (Tuesday, June 5, 2018)
[Federal Register Volume 83, Number 108 (Tuesday, June 5, 2018)]
[Rules and Regulations]
[Pages 25922-25936]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2018-11597]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R01-OAR-2017-0083; FRL-9978-27--Region 1]


Air Plan Approval; New Hampshire; Nonattainment Plan for the 
Central New Hampshire Sulfur Dioxide Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is approving the 
State Implementation Plan (SIP) revision that the State of New 
Hampshire submitted to EPA on January 31, 2017, for attaining the 1-
hour sulfur dioxide (SO2) primary national ambient air 
quality standard (NAAQS) for the Central New Hampshire Nonattainment 
Area. This plan (herein called a ``nonattainment plan'') includes New 
Hampshire's attainment demonstration and other elements required under 
the Clean Air Act (CAA). In addition to an attainment demonstration, 
the nonattainment plan addresses the requirements for meeting 
reasonable further progress (RFP) toward attainment of the NAAQS, 
implementation of reasonably available control measures and reasonably 
available control technology (RACM/RACT), base-year and projection-year 
emission inventories, enforceable emissions limitations and control 
measures, and contingency measures. EPA concludes that New Hampshire 
has appropriately demonstrated that the nonattainment plan provisions 
provide for attainment of the 2010 1-hour primary SO2 NAAQS 
in the Central New Hampshire Nonattainment Area by the applicable 
attainment date and that the nonattainment plan meets the other 
applicable requirements under the CAA. This action is being taken in 
accordance with the CAA.

DATES: This rule is effective on July 5, 2018.

ADDRESSES: EPA has established a docket for this action under Docket 
Identification No. EPA-R01-OAR-2017-0083. All documents in the docket 
are listed on the www.regulations.gov website. Although listed in the 
index, some information is not publicly available, i.e., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the internet 
and will be publicly available only in hard copy form. Publicly 
available docket materials are available at www.regulations.gov or at 
the U.S. Environmental Protection Agency, EPA New England Regional 
Office, Office of Ecosystem Protection, Air Permits Toxics and Indoor 
Programs Unit, 5 Post Office Square--Suite 100, Boston, MA. EPA 
requests that if at all possible, you contact the contact listed in the 
FOR FURTHER INFORMATION CONTACT section to schedule your inspection. 
The Regional Office's official hours of business are Monday through 
Friday, 8:30 a.m. to 4:30 p.m., excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: Leiran Biton, Air Permits, Toxics, and 
Indoor Programs Unit, U.S. Environmental Protection Agency, EPA New 
England Regional Office, 5 Post Office Square--Suite 100, (Mail code 
OEP05-2), Boston, MA 02109-3912, tel. (617) 918-1267, email 
biton.leiran@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' 
``us,'' or ``our'' is used, we mean EPA.

Table of Contents

I. Background and Purpose
II. Response to Comments
III. Final Action
IV. Incorporation by Reference
V. Statutory and Executive Order Reviews

I. Background and Purpose

    On June 22, 2010, EPA promulgated a new 1-hour primary 
SO2 NAAQS of 75 parts per billion (ppb), which is met at an 
ambient air quality monitoring site when the 3-year average of the 
annual 99th percentile of daily maximum 1-hour concentrations does not 
exceed 75 ppb, as determined in accordance with appendix T of 40 CFR 
part 50. See 75 FR 35520, codified at 40 CFR 50.17(a) and (b). On 
August 5, 2013, EPA designated a first set of 29 areas of the country 
as nonattainment for the 2010 SO2 NAAQS, including the 
Central New Hampshire Nonattainment Area within the State of New 
Hampshire. See 78 FR 47191, codified at 40 CFR part 81, subpart C. 
These ``round one'' area designations were effective October 4, 2013. 
Section 191(a) of the CAA directs states to submit SIPs for areas 
designated as nonattainment for the SO2 NAAQS to EPA within 
18 months of the effective date of the designation, i.e., by no later 
than April 4, 2015 in this case. These SIPs are required to demonstrate 
that their respective areas will attain the NAAQS as expeditiously as 
practicable, but no later than 5 years from the effective date of 
designation, which is October 4, 2018, in accordance with CAA sections 
191-192.
    Section 192(a) requires that such plans shall provide for NAAQS 
attainment as expeditiously as practicable, but no later than 5 years 
from the effective date of the nonattainment designation. Section 
172(c) of part D of the CAA lists the required components of a 
nonattainment plan submittal. The base year emissions inventory 
(section 172(c)(3)) is required to show a ``comprehensive, accurate, 
current inventory'' of all relevant pollutants in the nonattainment 
area. The nonattainment plan must identify and quantify any expected 
emissions from the construction of new sources to account for emissions 
in the area that might affect reasonable further progress (RFP) toward 
attainment, or that might interfere with attainment and

[[Page 25923]]

maintenance of the NAAQS, and it must provide for a nonattainment new 
source review (NNSR) program (section 172(c)(5)). The attainment 
demonstration must include a modeling analysis showing that the 
enforceable emissions limitations and other control measures taken by 
the state will provide for RFP and expeditious attainment of the NAAQS 
(section 172(c)(2), (4), (6), and (7)). The nonattainment plan must 
include an analysis and provide for implementation of the RACM 
considered, including RACT (section 172(c)(1)). Finally, the 
nonattainment plan must provide for contingency measures (section 
172(c)(9)) to be implemented either in the case that RFP toward 
attainment is not made, or in the case that the area fails to attain 
the NAAQS by the attainment date.
    On April 23, 2014, EPA issued a guidance document entitled, 
``Guidance for 1-Hour SO2 Nonattainment Area SIP 
Submissions.'' This guidance provides recommendations for the 
development of SO2 nonattainment SIPs to satisfy CAA 
requirements (see, e.g., sections 172, 191, and 192). An attainment 
demonstration must also meet the requirements of 40 CFR part 51, 
subparts F and G, and 40 CFR part 51, appendix W (the Guideline on Air 
Quality Models; ``the Guideline''), and include inventory data, 
modeling results, and emissions reduction analyses on which the state 
has based its projected attainment. The guidance also discusses 
criteria EPA expects to use in assessing whether emission limits with 
longer averaging times of up to 30 days ensure attainment of the 
SO2 NAAQS.
    For a number of areas, including the Central New Hampshire 
Nonattainment Area, EPA published a document on March 18, 2016, that 
pertinent states had failed to submit the required SO2 
nonattainment plan by the submittal deadline. See 81 FR 14736. This 
finding initiated a deadline under CAA section 179(a) for the potential 
imposition of new source review and highway funding sanctions, and for 
EPA to promulgate a federal implementation plan (FIP) under section 
110(c) of the CAA. In response to the requirement for SO2 
nonattainment plan submittals, New Hampshire submitted a nonattainment 
plan for the Central New Hampshire Nonattainment Area on January 31, 
2017. Pursuant to New Hampshire's January 31, 2017 submittal and EPA's 
subsequent completeness determination letter dated March 20, 2017, 
these sanctions under section 179(a) will not be imposed as a result of 
New Hampshire's having missed the April 4, 2015 submission deadline. 
Furthermore, with this current action issuing final approval of New 
Hampshire's SIP submittal, EPA's FIP obligation no longer applies, and 
no FIP will be imposed as a result of New Hampshire's missing the 
deadline.
    On November 29, 2017, EPA received a letter from New Hampshire 
correcting a misstatement in its January 2017 submittal to EPA. The 
State had earlier intended to modify its January 2017 submittal to EPA 
in response to a public comment on its draft nonattainment area plan, 
but inadvertently neglected to make the correction. Specifically, the 
State enclosed in its January 2017 submittal to EPA all comments and 
responses to comments relating to its draft nonattainment area plan, 
and among those was a set of comments submitted by Sierra Club to the 
State on January 5, 2017. Among other comments, Sierra Club asserted 
that the draft nonattainment area plan ``incorrectly suggests that an 
attainment demonstration can be made based on monitor readings alone,'' 
counter to EPA's April 2014 guidance, and stated that the plan should 
be revised to remove this inconsistency. In its response to that 
comment, New Hampshire indicated that it would remove the language per 
Sierra Club's comment, but inadvertently included the erroneous 
language nonetheless in its January 2017 submittal to EPA. New 
Hampshire's November 29, 2017 correction modifies the State's original 
submittal to exclude the erroneous language identified by Sierra Club, 
consistent with the State's response to comments. Hereafter, references 
to the State's January 31, 2017 SIP submittal are intended to include 
the November 29, 2017 correction.
    On September 28, 2017 (82 FR 45242), EPA proposed to approve New 
Hampshire's January 31, 2017 nonattainment plan submittal and 
SO2 attainment demonstration. The State's submittal and 
attainment demonstration included all the specific attainment elements 
mentioned above, including new SO2 emission limits found to 
be comparably stringent to the 1-hour form of the primary 
SO2 NAAQS and associated control technology efficiency 
requirements for the electric generating source Merrimack Station, 
currently owned and operated by GSP Merrimack LLC and formerly by 
Public Service of New Hampshire (PSNH) d/b/a Eversource Energy, 
impacting the Central New Hampshire Nonattainment Area. Merrimack 
Station's new SO2 emission limits were developed in 
accordance with EPA's April 2014 guidance. Comments on EPA's proposed 
rulemaking were due on or before October 30, 2017. EPA received a 
single set of comments on the proposed approval of New Hampshire's 
nonattainment area plan for the Central New Hampshire Nonattainment 
Area. The comments are available in the docket for this final 
rulemaking action. EPA's summary of the comments and EPA's responses 
are provided below. For a comprehensive discussion of New Hampshire's 
SIP submittal and EPA's analysis and rationale for approval of the 
State's submittal and attainment demonstration for this area, please 
refer to EPA's September 28, 2017 notice of proposed rulemaking.
    The remainder of this preamble summarizes EPA's final approval of 
New Hampshire's SIP submittal and attainment demonstration for the 
Central New Hampshire Nonattainment Area and contains EPA's response to 
public comments.

II. Response to Comments

    The single set of comments addressing the proposed approval of the 
SIP revision for the Central New Hampshire Nonattainment Area was 
received from Sierra Club on October 30, 2017. The Sierra Club's 
October 30, 2017 comments explicitly incorporated a July 15, 2016 
comment letter with supporting attachments submitted to New Hampshire 
by Sierra Club on behalf of both Sierra Club and Conservation Law 
Foundation (CLF) regarding the State's proposed permit for Merrimack 
Station. Because the October 30, 2017 Sierra Club comments on EPA's 
proposal are nearly identical to the prior July 15, 2016 comments, 
except where the October 30, 2017 comments provide updated information, 
EPA's responses to the October 30, 2017 Sierra Club comments also serve 
to respond to issues raised in the July 15, 2016 comments to the State, 
except where EPA identifies discussion as specifically applying only to 
comments from July 15, 2016. In the following discussion, EPA will 
refer to the Sierra Club or Sierra Club/CLF as ``the Commenter.'' To 
review the complete set of comments received, refer to the docket for 
this rulemaking as identified above. A summary of the comments received 
and EPA's responses are provided below.
    Comment 1: The commenter asserted that the proposed 7-day average 
limit on emissions from Merrimack Station is insufficient to protect 
the 1-hour NAAQS. The commenter indicated that short-term exposure to 
SO2 for as little as five minutes has significant health 
impacts and causes decrement in lung function, aggravation of asthma, 
chest tightness, and respiratory and

[[Page 25924]]

cardiovascular morbidity. The commenter stated that such short-term 
exposure is especially risky for children with asthma. To support these 
statements regarding health effects, the commenter cited several EPA 
documents related to the final SO2 NAAQS and air quality 
trends. The commenter stated that EPA changed the NAAQS from 140 ppb 
averaged over 24 hours to 75 ppb averaged over one hour in order to 
address these health impacts. The commenter stated that as a result of 
the form of the standard, which is evaluated through reference to the 
fourth-highest daily maximum hourly-average concentrations in each 
year, emission limits with an averaging period longer than one hour are 
highly unlikely to be able to protect the 1-hour NAAQS. The commenter 
indicated that the form of the NAAQS means that ambient air quality can 
be evaluated as unsafe with as few as four hours of elevated emissions 
over the course of a year. The commenter stated that even if the 7-day 
limit is complied with, possible short-term emission ``spikes'' that 
may coincide with startup, shutdown, or control system malfunction 
events, for example, could nevertheless cause ambient 1-hour 
SO2 concentrations sufficient to violate the NAAQS. In 
support of this point, the commenter provided language making similar 
points excerpted from two EPA letters that had been included in the 
attachments to the commenter's July 15, 2016 comments to New Hampshire, 
specifically an August 12, 2010 comment letter from EPA Region 7 to 
Kansas regarding the Sunflower Holcomb Station Expansion Project, and a 
February 1, 2012 comment letter from EPA Region 5 to Michigan regarding 
a draft construction permit for the Detroit Edison Monroe Power Plant. 
The commenter concluded that the 7-day limit proposed for inclusion in 
the State's SIP has an averaging period that is 168 times longer than 
that of the 1-hour NAAQS and should be revised to adequately protect 
the NAAQS. The commenter added that hourly emissions limits are not 
unreasonable, and cited several examples of permits that impose such 
limits. Therefore, the commenter concluded that a 1-hour emissions 
limit should be imposed.
    Response 1: EPA appreciates the commenter's concerns about the 
appropriateness of approving nonattainment plans with emission 
limitations that apply over a longer time period than the 1-hour form 
of the 2010 SO2 NAAQS. We discussed similar issues in EPA's 
April 2014 guidance. In this case, EPA has concluded that the approach 
employed by New Hampshire to develop the emission limitations for 
Merrimack Station and included in the State's SIP submittal is 
consistent with recommendations discussed in EPA's April 2014 guidance 
and adequately protects against violation of the 1-hour SO2 
NAAQS. EPA's rationale for this conclusion is explained in further 
detail below.
    The health effects information provided by the commenter is not in 
dispute in this rulemaking. This rulemaking instead addresses whether 
New Hampshire's plan is adequate to meet the previously established 
NAAQS.
    As mentioned above, CAA section 172(c) directs states with areas 
designated as nonattainment to demonstrate that the submitted 
nonattainment plan provides for attainment of the NAAQS. EPA's rules at 
40 CFR part 51, subpart G further delineate the control strategy 
requirements that SIPs must meet, and EPA has long required that all 
control strategies in nonattainment plans reflect four fundamental 
principles of quantification, enforceability, replicability, and 
accountability. See ``State Implementation Plans; General Preamble for 
the Implementation of Title I of the Clean Air Act Amendments of 1990; 
Proposed Rule,'' 57 FR 13498 (April 16, 1992) (General Preamble), at 
13567-68. Additional guidance is provided in EPA's April 2014 guidance. 
For SO2, there are generally two components needed to 
support an attainment demonstration submitted under section 172(c): (1) 
Emission limitations and other control measures that assure 
implementation of permanent, enforceable, and necessary emission 
controls; and (2) a modeling analysis that meets the requirements of 40 
CFR part 51, appendix W and demonstrates that these emission 
limitations and control measures provide for timely attainment of the 
primary SO2 NAAQS as expeditiously as practicable, but by no 
later than the applicable attainment date for the affected area. In all 
cases, the emission limitations and control measures must be 
accompanied by appropriate methods and conditions to determine 
compliance with the respective emission limitations and control 
measures. Furthermore, in all cases, the emission limitations and 
control measures must be: Quantifiable (i.e., a specific amount of 
emission reduction can be ascribed to the measures), fully enforceable 
(specifying clear, unambiguous, and measurable requirements for which 
compliance can be practicably determined), replicable (the procedures 
for determining compliance are sufficiently specific and non-subjective 
such that two independent entities applying the procedures would obtain 
the same result), and accountable (source specific limitations must be 
permanent and must reflect the assumptions used in the SIP 
demonstrations).
    In our April 2014 guidance, EPA notes that past Agency guidance has 
recommended that averaging times in SO2 SIP emissions 
limitations should not exceed the averaging time of the applicable 
NAAQS that the limit is intended to help attain (e.g., addressing 
emissions averaged over one or three hours). EPA's April 2014 guidance 
also discusses the possibility of utilizing emission limitations with 
longer averaging times of up to 30 days, so long as the state meets 
various suggested criteria to show that the longer-term limits are 
comparably stringent to the 1-hour critical emission value that is 
needed to meet the NAAQS. See EPA's April 2014 guidance, pp. 22 to 39. 
The guidance recommends that--should states elect to use longer 
averaging times--the longer-term average limit should be set at an 
adjusted level to reflect a stringency comparable to the 1-hour average 
critical emission value shown to provide for attainment through a 
modeling analysis that the plan otherwise would have set as an emission 
limit.
    At the outset, EPA notes that the specific examples of earlier EPA 
statements cited by the commenter (i.e., those contained in Exhibits 1, 
2, 3, and 4 to Appendix A of the comment submission) all pre-date the 
release of EPA's April 2014 guidance. As such these examples only 
reflect the Agency's development of its policy for implementing the 
2010 SO2 NAAQS as of the dates of their own issuance. At the 
time of their issuance, EPA had not yet addressed the specific question 
of whether it might be possible to devise an emission limit with an 
averaging period longer than 1-hour, with appropriate adjustments that 
would make it comparably stringent to an emission limit shown to attain 
1-hour emission level, that could adequately ensure attainment of the 
SO2 NAAQS. None of the pre-2014 EPA documents cited by the 
commenter address this question; consequently, it is not reasonable to 
read any of them as rejecting that possibility. However, EPA's April 
2014 guidance specifically addressed this issue as it pertains to 
requirements for SIPs for SO2 nonattainment areas under the 
2010 NAAQS, especially with regard to the use of appropriately set 
comparably stringent limitations based on averaging

[[Page 25925]]

times as long as 30 days (see p. 2). EPA developed this guidance 
pursuant to a lengthy stakeholder outreach process regarding 
implementation strategies for the 2010 NAAQS, which had not yet 
concluded (or in some cases even begun) when the documents cited by the 
commenter were issued. As such, EPA's April 2014 guidance was the first 
instance in which the Agency provided recommended guidance for that 
component of this action. Consequently, EPA does not view those prior 
EPA statements as conflicting with the Agency's guidance addressing 
this specific question of how to devise a longer-term limit that is 
comparably stringent to a 1-hour critical emission value that has been 
modeled to attain the NAAQS. Moreover, EPA notes that the commenter has 
not raised specific objections to the general policy and technical 
rationale EPA provided in its proposed approval or in EPA's April 2014 
guidance for why such longer-term averaging-based limits may in 
specific cases be adequate to ensure NAAQS attainment, which we again 
summarize below.
    EPA's April 2014 guidance provides an extensive discussion of EPA's 
rationale for positing that an appropriately-set, comparably stringent 
limitation based on an averaging time as long as 30 days can, based on 
a situation's specific facts, be found to provide for attainment of the 
2010 primary SO2 NAAQS, provided it is shown to be 
comparably stringent to a 1-hour critical emission value that is 
demonstrated through modeling to attain the NAAQS. Essentially, to 
achieve such comparable stringency, rather than simply convert an 
attaining 1-hour emission rate to a longer term limit at the same 
level, it is expected that an adjustment would be needed to lower the 
emission rate as the averaging time is increased. It is first necessary 
to identify a modeled 1-hour emission value that attains the NAAQS 
before deriving a comparably stringent longer-term emission limit, 
i.e., an emission limit that has been appropriately adjusted downward. 
In evaluating this option, EPA considered in the April 2014 guidance 
the nature of the standard, conducted detailed analyses of the impact 
of the use of 30-day average limits on the prospects for attaining the 
standard, and carefully reviewed how best to achieve an appropriate 
balance among the various factors that warrant consideration in judging 
whether a state's nonattainment plan provides for attainment. Id. at 
pp. 22 to 39. See also id. at appendices B, C, and D.
    As specified in 40 CFR 50.17(b), the 1-hour primary SO2 
NAAQS is met at an ambient air quality monitoring site when the 3-year 
average of the annual 99th percentile of daily maximum 1-hour 
concentrations is less than or equal to 75 ppb. In a year with 365 days 
of valid monitoring data, the 99th percentile would be the fourth 
highest daily maximum 1-hour value. The 2010 SO2 NAAQS, 
including this form of determining compliance with the standard, was 
upheld by the U.S. Court of Appeals for the District of Columbia 
Circuit in Nat'l Envt'l Dev. Ass'n's Clean Air Project v. EPA, 686 F.3d 
803 (D.C. Cir. 2012). Because the standard has this form, a single 
exceedance of the numerical limit of 75 ppb does not constitute a 
violation of the standard. Instead, at issue is whether a source 
operating in compliance with a properly set longer-term average could 
cause exceedances, and if so the resulting frequency and magnitude of 
such exceedances. In particular, what matters is whether EPA can have 
reasonable confidence that a properly set longer-term average limit 
will provide that the 3-year average of annual fourth highest daily 
maximum values will be at or below 75 ppb. A synopsis of EPA's review 
of how to judge whether such plans ``provide for attainment,'' based on 
modeling of projected allowable emissions and in light of the form for 
determining attainment of the NAAQS at monitoring sites, follows.
    For SO2 nonattainment plans based on 1-hour emission 
limits, the standard approach is to conduct modeling using fixed 
emission rates. The maximum emission rate that would be modeled to 
result in attainment (i.e., in an ``average year'' \1\ shows fewer than 
four days with maximum hourly levels exceeding 75 ppb) is labeled the 
``critical emission value.'' The modeling process for identifying this 
critical emission value inherently considers the numerous variables 
that affect ambient concentrations of SO2, such as 
meteorological data, background concentrations, and terrain. In the 
standard approach, the state would then provide for attainment by 
setting a continuously applicable 1-hour emission limitation at this 
critical emission value.
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    \1\ An ``average year'' is used to mean a year with average air 
quality. While 40 CFR part 50, appendix T provides for averaging 
three years of 99th percentile daily maximum values (e.g., the 
fourth highest maximum daily concentration in a year with 365 days 
with valid data), this discussion and an example used later in EPA's 
response to Comment 1 uses a single ``average year'' in order to 
simplify the illustration of relevant principles.
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    EPA recognizes that some sources may have highly variable 
emissions, for example due to variations in fuel sulfur content and 
operating rate, that can make it extremely difficult, even with a well-
designed control strategy, to ensure in practice that emissions for any 
given hour do not exceed the critical emission value. EPA also 
acknowledges the concern that longer-term emission limits can allow 
short periods with emissions above the critical emission value, which, 
if coincident with meteorological conditions conducive to high 
SO2 concentrations, could create the possibility of a NAAQS 
exceedance occurring on a day when an exceedance would not have 
occurred if emissions were continuously controlled at the level 
corresponding to the 1-hour critical emission value. However, for 
several reasons, EPA finds that the approach recommended in its April 
2014 guidance document suitably addresses this concern, and that in 
this case, New Hampshire has devised a longer-term limit that is 
comparably stringent to the 1-hour critical emission value that 
suitably provides for meeting the NAAQS.
    First, from a practical perspective, EPA expects the actual 
emission profile of a source subject to an appropriately set longer-
term average limit to be similar to the emission profile of a source 
subject to an analogous 1-hour average limit. EPA expects this 
similarity because it has recommended that the longer-term average 
limit be set at a level that is comparably stringent to the otherwise 
applicable 1-hour limit (reflecting a downward adjustment from the 
critical emission value) and that takes the source's emissions profile 
into account. As a general matter, EPA would expect that any emission 
limit with an averaging time longer than 1 hour would need to reflect a 
downward adjustment to compensate for the loss of stringency inherent 
in applying a longer term average limit. This expectation is based on 
the idea that a limit based on the 30-day average of emissions, for 
example, at a particular level is likely to be a less stringent limit 
than a 1-hour limit at the same level, since the control level needed 
to meet a 1-hour limit every hour is likely to be greater than the 
control level needed to achieve the same limit on a 30-day average 
basis. EPA's approach for downward adjustment is to account for the 
expected variability in emissions over the time period up to 30 days to 
achieve comparable stringency to the emissions and expected air quality 
impacts for a 1-hour period. As a result, EPA expects

[[Page 25926]]

either form of emission limit to yield comparable air quality.
    Second, from a more theoretical perspective, EPA has compared the 
likely air quality with a source having maximum allowable emissions 
under an appropriately set longer-term limit, as compared to the likely 
air quality with the source having maximum allowable emissions under 
the comparable 1-hour limit. In this comparison, in the 1-hour average 
limit scenario, the source is presumed at all times to emit at the 
critical emission value, and in the longer-term average limit scenario, 
the source is presumed occasionally to emit more than the critical 
emission value but on average, and presumably at most times, to emit 
well below the critical emission value. In an ``average year,'' 
compliance with the 1-hour limit is expected to result in three 
exceedance days (i.e., three days with maximum hourly values above 75 
ppb) and a fourth day with a maximum hourly value at 75 ppb. By 
comparison, with the source complying with a longer-term limit, it is 
possible that additional exceedances would occur that would not occur 
in the 1-hour limit scenario (if emissions exceed the critical emission 
value at times when meteorology is conducive to poor air quality). 
However, this comparison must also factor in the likelihood that 
exceedances that would be expected in the 1-hour limit scenario would 
not occur in the longer-term limit scenario. This result arises because 
the longer-term limit requires lower emissions most of the time 
(because the limit is set below the critical emission value), so a 
source complying with an appropriately set longer-term limit is likely 
to have lower emissions at critical times than would be the case if the 
source were emitting as allowed with a 1-hour limit.
    As a hypothetical example to illustrate these points, suppose a 
source that always emits 1,000 pounds of SO2 per hour, which 
results in air quality exactly at the level of the NAAQS (i.e., results 
in a design value of 75 ppb). Suppose further that in an ``average 
year,'' these emissions cause the five highest maximum daily average 1-
hour concentrations to be 100 ppb, 90 ppb, 80 ppb, 75 ppb, and 70 ppb. 
Then suppose that the source becomes subject to a 30-day average 
emission limit of 700 pounds per hour, i.e., at a level adjusted 
downward from 1,000 pounds per hour by 30%. It is theoretically 
possible for a source meeting this limit to have emissions that 
occasionally exceed 1,000 pounds per hour, but with a typical emissions 
profile emissions would much more commonly be between 600 and 800 
pounds per hour. In this simplified example, assume a zero background 
concentration, which allows one to assume a linear relationship between 
emissions and air quality. (A nonzero background concentration would 
make the mathematics more difficult but would give similar results.) 
Air quality will depend on how much emissions occur on which critical 
hours, but suppose that emissions at the relevant times on these five 
days are 800 pounds per hour, 1,100 pounds per hour, 500 pounds per 
hour, 900 pounds per hour, and 1,200 pounds per hour, respectively. 
(This is a conservative example because the average of these emissions, 
900 pounds per hour, is well over the 30-day average emission limit of 
700 pounds per hour.) These emissions would result in daily maximum 1-
hour concentrations of 80 ppb, 99 ppb, 40 ppb, 67.5 ppb, and 84 ppb. In 
this example, the fifth day would have an exceedance that would not 
otherwise have occurred, but the third and fourth days would not have 
exceedances that otherwise would have occurred. In this example, the 
fourth highest maximum daily concentration under the 30-day average 
would be 67.5 ppb.
    This simplified example illustrates the findings of a more 
complicated statistical analysis that EPA conducted using a range of 
scenarios using actual plant data. As described in appendix B of EPA's 
April 2014 guidance, EPA found that the requirement for lower average 
emissions is highly likely to yield better air quality than is required 
with a comparably stringent 1-hour limit. Based on analyses described 
in appendix B, EPA expects that an emission profile with maximum 
allowable emissions under an appropriately set comparably stringent 30-
day average limit is likely to have the net effect of having a lower 
number of exceedances and better air quality than an emission profile 
with maximum allowable emissions under a 1-hour emission limit at the 
critical emission value. This result provides a compelling rationale 
for allowing the use of a longer averaging period, in appropriate 
circumstances where the facts indicate that this result can be expected 
to occur.
    The question then becomes whether this approach--which is likely to 
produce a lower number of overall exceedances even though it may 
produce some unexpected exceedances above the 1-hour critical emission 
value--meets the requirement in sections 110(a) and 172(c) for state 
implementation plans to ``provide for attainment'' of the NAAQS. For 
SO2, as for other pollutants, it is generally impossible to 
design a nonattainment plan in the present that will guarantee that 
attainment will occur in the future. A variety of factors can cause a 
well-designed nonattainment plan to fail and unexpectedly not result in 
attainment, for example if meteorology occurs that is more conducive to 
poor air quality than was anticipated in the plan. Therefore, in 
determining whether a plan meets the requirement to provide for 
attainment, EPA's task is commonly to judge not whether the plan 
provides absolute certainty that attainment will in fact occur, but 
rather whether the plan provides an adequate level of confidence of 
prospective NAAQS attainment. From this perspective, in evaluating use 
of a longer-term limit up to 30-days, EPA must weigh the likely net 
effect on air quality. Such an evaluation must consider the risk that 
occasions with meteorology conducive to high concentrations will have 
elevated emissions leading to exceedances that would not otherwise have 
occurred, and must also weigh the likelihood that the requirement for 
lower emissions on average will result in days not having exceedances 
that would have been expected with emissions at the critical emission 
value. Additional policy considerations, such as in this case the 
desirability of accommodating real world emissions variability without 
significant risk of violations, are also appropriate factors for EPA to 
weigh in judging whether a plan provides a reasonable degree of 
confidence that the plan will lead to attainment. Based on these 
considerations, especially given the high likelihood that a 
continuously enforceable limit, averaged over as long as 30 days, 
determined in accordance with EPA's April 2014 guidance, will result in 
attainment, EPA posits as a general matter that such limits, if 
appropriately determined, can reasonably be considered to provide for 
attainment of the 2010 SO2 NAAQS. Furthermore, as discussed 
below, EPA concludes that in this case, New Hampshire has demonstrated 
that its longer-term limit was appropriately determined and provides 
for NAAQS attainment.
    As stated by the commenter, the limit included in the State's SIP 
submittal is for a period of 7 days, or 168 hours. As stated above, EPA 
posits that limits based on periods of as long as 30 days (720 hours), 
determined in accordance with our April 2014 guidance, can, in many 
cases, be reasonably considered to provide for attainment of the 2010 
SO2 NAAQS. In EPA's April 2014 guidance, EPA supplied an 
analysis of the impact of emissions variability on air quality

[[Page 25927]]

and explained that it may be possible in some specific cases to develop 
control strategies that account for variability in 1-hour emissions 
rates through emissions limits with averaging times as long as 30 days 
and still provide for attainment of the 2010 SO2 NAAQS. 
Since seven days (168 hours) are well within the period of 30 days (720 
hours), EPA has concluded that a limit for Merrimack Station based on a 
period of 7 days and determined in accordance with EPA's April 2014 
guidance can be reasonably considered to provide for attainment.
    EPA's April 2014 guidance offers specific recommendations for 
determining an appropriate longer-term average limit. The recommended 
method starts with determination of the 1-hour emission limit that 
would provide for attainment (i.e., the 1-hour critical emission 
value), and applies an adjustment factor to determine the (lower) level 
of the longer term average emission limit that would be estimated to 
have a stringency comparable to the otherwise necessary 1-hour emission 
limit. This method uses a database of continuous emission data 
reflecting the type of control that the source will be using to comply 
with the SIP emission limits, which (if compliance requires new 
controls) may require use of a different emission database, e.g., from 
a different but comparable facility using similar emissions control 
equipment. The recommended method involves using these data to compute 
a complete set of emission averages, computed according to the 
averaging time and averaging procedures of the prospective emission 
limitation. In this recommended method, the ratio of the 99th 
percentile among these longer-term averages to the 99th percentile of 
the 1-hour values represents an adjustment factor that may be 
multiplied by the candidate 1-hour emission limit (i.e., the critical 
emission value) to determine a longer-term average emission limit that 
may be considered comparably stringent.\2\ The guidance also addresses 
a variety of related topics, such as the potential utility of setting 
supplemental emission limits, such as mass-based limits, to reduce the 
likelihood and/or magnitude of elevated emission levels that might 
occur under the longer-term emission rate limit.
---------------------------------------------------------------------------

    \2\ For example, if the critical emission value is 1,000 pounds 
of SO2 per hour, and a suitable adjustment factor is 
determined to be 0.70 (i.e., 70%), the recommended longer term 
average limit would be 700 pounds per hour.
---------------------------------------------------------------------------

    Preferred air quality models for use in regulatory applications are 
described in appendix A of the Guideline (40 CFR part 51, appendix 
W).\3\ In 2005, EPA promulgated AERMOD as the Agency's preferred near-
field dispersion modeling for a wide range of regulatory applications 
addressing stationary sources (for example in estimating SO2 
concentrations) in all types of terrain based on extensive 
developmental and performance evaluation. Supplemental guidance on 
modeling for purposes of demonstrating attainment of the SO2 
standard is provided in appendix A to EPA's April 2014 guidance. 
Appendix A provides extensive guidance on the modeling domain, the 
source inputs, assorted types of meteorological data, and background 
concentrations. Consistency with the recommendations in this guidance 
is generally necessary for the attainment demonstration to offer 
adequately reliable assurance that the plan provides for attainment.
---------------------------------------------------------------------------

    \3\ The most recent version of the Guideline was published on 
January 17, 2017 (see 82 FR 5182) and became effective on May 22, 
2017.
---------------------------------------------------------------------------

    As stated previously, attainment demonstrations for the 2010 1-hour 
primary SO2 NAAQS must demonstrate future attainment and 
maintenance of the NAAQS in the entire area designated as nonattainment 
(i.e., not just at the violating monitor) by using air quality 
dispersion modeling (see appendix W to 40 CFR part 51) to show that the 
mix of sources and enforceable control measures and emission rates in 
an identified area will not lead to a violation of the SO2 
NAAQS. For a short-term (i.e., 1-hour) standard, EPA asserts that 
dispersion modeling, using allowable emissions and addressing 
stationary sources in the affected area (and in some cases those 
sources located outside the nonattainment area which may affect 
attainment in the area) is technically appropriate, efficient, and 
effective in demonstrating attainment in nonattainment areas because it 
takes into consideration combinations of meteorological and emission 
source operating conditions that may contribute to peak ground-level 
concentrations of SO2.
    Regarding the commenter's position that only hourly SO2 
emissions limits are reasonable, citing the examples supplied in the 
commenter's submission, EPA agrees that 1-hour limits can be reasonable 
and protective so long as they are adequately supported by an 
attainment demonstration establishing those limits as meeting the 
NAAQS. In this action, EPA is not changing its position regarding the 
sufficiency in meeting the NAAQS with 1-hour emissions limitations to 
which other facilities, as cited by the commenter, are subject. The 
fact that New Hampshire could reasonably have chosen to establish 1-
hour limits does not mean that EPA should disapprove limits with 
comparable stringency using longer averaging times. In this instance, 
the State's emission limit for Merrimack Station utilizes a 7-day 
average, and New Hampshire has shown it to be comparably stringent to a 
1-hour limit at the critical emission level, which the State 
demonstrated to suitably provide for attainment of the NAAQS.
    Based on EPA's review of the State's submittal, EPA finds that the 
7-day average limit of 0.39 pounds (lb) per million British thermal 
units (MMBtu) established for Merrimack Station provides for a suitable 
alternative to establishing a 1-hour average emission limit for this 
source. New Hampshire used a suitable data profile in an appropriate 
manner and has thereby applied an appropriate adjustment, yielding 
emission limits that have comparable stringency to the 1-hour average 
limit that the State determined would otherwise have been necessary to 
provide for attainment. While the longer-term averaging limit allows 
occasions in which emissions may be higher than the level that would be 
allowed with the 1-hour limit, the State's limits compensate by 
requiring average emissions to be adequately lower than the level that 
would otherwise have been required by a 1-hour average limit. The 
September 28, 2017 notice of proposed rulemaking provided a detailed 
description of EPA's rationale for the proposed finding that the 7-day 
average limit for Merrimack Station is adequate to provide for 
attainment, and the commenter has not raised any concerns about this 
approach that we have not already addressed.
    Comment 2: The commenter states that the 7-day average approach 
would mask significant hours in which emissions are above safe levels. 
The commenter then presents information regarding historic hourly 
emissions from Merrimack Station after the flue gas desulfurization 
(FGD) scrubber system was installed. Specifically, using data from 
EPA's Air Markets Program Data (AMPD), the commenter identified over 
224 individual hours on 62 separate days in the period between January 
1, 2012, through September 30, 2017, during which emissions were above 
the 1-hour critical emission rate of 0.54 lb/MMBtu,\4\ i.e., the 
maximum

[[Page 25928]]

hourly emission rate determined to be protective of the NAAQS. The 
commenter indicated that during the same period, there do not appear to 
have been any 7-day periods in which average emissions exceeded the 
0.39 lb/MMBtu limit in the SIP revision. The commenter asserts that 
this disparity, i.e., the fact that emissions during over 224 hours on 
62 separate days exceeded the 1-hour critical emission rate of 0.54 lb/
MMBtu while the 7-day limit was not exceeded during the time period 
from January 2012 through September 2017, indicates that the downwardly 
adjusted 0.39 lb/MMBtu 7-day limit is inadequate to protect the NAAQS.
---------------------------------------------------------------------------

    \4\ In multiple instances, the Commenter appears to inaccurately 
assume the critical emission rate is 0.53 lb/MMBtu. The mass-based 
critical emission value, as calculated by the State's modeling, is 
2,544 lb/hour, which is equivalent to the critical emission rate of 
0.54 lb/MMBtu at the maximum rated capacity of Merrimack's two coal-
fired electric generating units, MK1 and MK2.
---------------------------------------------------------------------------

    Response 2: The commenter implies that occasions of emissions above 
the 1-hour critical emission rate, notwithstanding compliance with a 7-
day limit, create an unacceptable risk of additional exceedances that 
would result in violation of the standard. EPA does not agree with this 
notion, and the commenter has not supplied evidence to support it. 
Furthermore, in making this claim, the commenter is relying on an 
emissions dataset that, for the reasons enumerated below, is not 
appropriate for assessing the prospective likelihood of Merrimack 
Station emitting more than the critical emission value, which may 
result in unsafe air quality. First, the dataset includes emissions 
from periods during which Merrimack Station was not subject to State 
permit conditions on the operation of its FGD scrubber system, and is 
therefore not representative of current and expected future emissions. 
Second, the dataset includes some emission values that are 
unrealistically high because they are calculated or substitute data 
used for purposes of determining compliance with EPA's Acid Rain 
Program rather than measured data used for determining emissions for 
compliance with the 7-day limit. Third, emission data for Merrimack 
Station show that the facility has rarely emitted above the critical 
emission rate of 0.54 lb/MMBtu since September 1, 2016, when the 
State's permit TP-0189 became applicable and enforceable. Fourth, the 
State's rate-based emission limit is designed to ensure consistent 
control at all load levels during operation, so an exceedance of the 
critical emission rate (in lb/MMBtu) does not necessarily mean that 
emissions are higher than the critical emission value (in lb/hour). 
Fifth and finally, if actual measured emissions from Merrimack Station 
had occurred at the levels indicated by the commenter, the facility 
would have violated the current 7-day emission limit, had it been in 
place at the time, and therefore these data are not evidence that 
compliance with the 7-day limit would result in a higher risk of NAAQS 
violations. Each of these points is discussed in greater detail below.
    By reviewing the AMPD emissions data using EPA's Field Audit 
Checklist Tool (FACT) \5\ for the period between January 1, 2012, and 
March 31, 2018, EPA found 227 hours with emissions above 0.54 lb/MMBtu, 
a number that is consistent with the ``over 224 hours'' identified by 
the commenter. In the following discussion, EPA identifies the number 
of hours of those 227 hours that are not appropriate to use in the 
analysis of the adequacy of the 7-day emission limit. EPA has included 
a spreadsheet in the docket of this action which contains the relevant 
data used in EPA's analysis.
---------------------------------------------------------------------------

    \5\ Field Audit Checklist Tool (FACT) version 1.2.0.1, available 
for download at: www.epa.gov/airmarkets/field-audit-checklist-tool-fact. FACT provides users with metadata, including ``method of 
determination codes'' (MODC), beyond the information available using 
the AMPD website referenced by the Commenter.
---------------------------------------------------------------------------

    (1) The FGD at Merrimack Station first became operational on 
September 28, 2011. Under the conditions established in the State's 
permit TP-0008, Merrimack Station was not permitted to operate MK2, one 
of its two utility boilers, unless the FGD was in operation. Merrimack 
Station's other utility boiler, MK1, was permitted to bypass the FGD 
system for no more than 840 hours per consecutive 12-month period. Both 
of these permit conditions became applicable and enforceable as of July 
1, 2013. (This emission bypass provision is no longer permitted under 
the September 1, 2016 TP-0189 permit.) Prior to July 1, 2013, the 
facility was not subject to enforceable permit conditions requiring 
operation of the FGD. During 2012, Merrimack Station bypassed the FGD 
for emissions from MK1 on several occasions, the last of which occurred 
on November 7, 2012. As such, EPA does not view emissions occurring at 
Merrimack Station prior to July 1, 2013 as being representative of 
current or expected future emissions because prior to this date the 
relevant, enforceable permit provisions that required operation of the 
emission control system at Merrimack Station, as contained in permit 
number TP-0008, were not effective. Of the 227 hours with emissions 
above 0.54 lb/MMBtu, there were 188 hours that occurred prior to July 
1, 2013, leaving 39 hours for further analysis.
    (2) Merrimack Station is subject to emission monitoring and 
reporting requirements under the Acid Rain Program (40 CFR part 75). 
Under the Acid Rain Program, Merrimack Station must hold sufficient 
emission allowances to account for its SO2 emissions. For 
hours in which direct, quality-assured measurements from the continuous 
monitoring systems (CEMS) are not available, EPA's Acid Rain Program 
regulations require that high emission values are calculated or 
substituted for the emissions that are not monitored in order to ensure 
that the source holds sufficient allowances to account conservatively 
for its emissions. See 40 CFR part 75 subpart D. As described in New 
Hampshire's response to comments for its nonattainment area plan, the 
CEMS at Merrimack Station was certified on November 21, 2011 using only 
the low range of a dual range analyzer to measure from 0 to 300 parts 
per million (ppm) SO2 of in-stack exhaust gas. When the low 
range was exceeded, i.e., in-stack exhaust gas exceeded 300 ppm 
SO2, a calculated value of 200% of the maximum potential or 
uncontrolled concentration was reported to ensure that under reporting 
did not occur for purposes of the Acid Rain Program. As part of a 
periodic reassessment of the appropriate analyzer ranges, Merrimack 
Station retained a low range configuration and adjusted it to measure 
from 0 to 150 ppm on January 28, 2013. See section 2.1.1.5 of appendix 
A to 40 CFR part 75. On February 4, 2015, Merrimack Station began 
calibrating and quality-assuring the high range of the dual range 
analyzer from 150 to 2,600 ppm, while the lower range continued to be 
quality assured to measure between 0 and 150 ppm. In accordance with 
Acid Rain Program requirements, Merrimack Station was required to 
report calculated emissions at 200% of the maximum potential or 
uncontrolled concentration during the period from November 21, 2013 to 
February 4, 2015 when concentrations exceeded the lower range, i.e., 
in-stack exhaust gas exceeded 300 ppm. See section 2.1.1.4(f) of 
Appendix A to 40 CFR part 75. These hours are marked as SO2 
Method Of Determination Code (MODC) 19 in the FACT database and were 
reported as such in the hourly electronic emissions records. Additional 
CEMS outage hours that used substitute data calculated as the average 
of the hour before and after, reported as SO2 MODC 06, are 
not measured emissions data but rather are substitute data hours. EPA 
concludes from the CEMS data that data points flagged as calculated or 
substitute data

[[Page 25929]]

with SO2 MODC 06 or 19 are not appropriate for use in 
assessing NAAQS compliance in this case because these values do not 
represent actual measured emissions during those hours.
    Data points flagged as SO2 MODC 06 or 19 account for 32 
hours of the remaining 39 emissions data points over 0.54 lb/MMBtu, 
leaving seven hours for further analysis.
    (3) The emission profile for Merrimack Station, since the issuance 
of the September 2016 permit containing the 7-day average 
SO2 emissions limit, shows that exceedances of the critical 
emission rate, i.e., 0.54 lb/MMBtu, are infrequent. In the period from 
September 1, 2016, when the State's permit TP-0189 became applicable 
and enforceable, to March 31, 2018, Merrimack Station has emitted at a 
level higher than the 0.54 lb/MMBtu on three hours out of 3,109 
operating hours with measured emissions data, or less than 0.1%. In 
addition to the SO2 emission limit, the September 1, 2016 
permit TP-0189 included a more stringent limit for the SO2 
removal efficiency of the scrubber than was included in the TP-0008 
permit. In addition, TP-0189 prohibits the use of the emergency stack 
to bypass emissions controls except as necessary to prevent severe 
damage to equipment or potential injury to facility personnel. The 
infrequency of emissions above 0.54 lb/MMBtu since September 1, 2016 
indicates that the multiple SO2 emission control provisions 
contained in TP-0189, as described above, have been successful in 
consistently reducing emissions from Merrimack Station. Based on this 
evidence, EPA expects that future instances of emissions from Merrimack 
Station above 0.54 lb/MMBtu will continue to be extremely rare.
    (4) While emissions exceeded 0.54 lb/MMBtu during each of the seven 
hours since July 1, 2013 (of which only three hours exceeded 0.54 lb/
MMBtu since September 1, 2016, as described above), for six of these 
hours the total mass-based emission rate, measured in lb/hour, did not 
exceed the critical emission value of 2,544 lb/hour. Of those six 
hours, the highest emission level was 1,386.6 pounds of SO2, 
well below the critical emission value, and the other emission values 
range from 1.1 to 843.5 pounds SO2. Based on the State's 
attainment modeling demonstration, these lower emission values would 
not be expected to result in exceedances of the NAAQS. That is, New 
Hampshire's modeling indicates that Merrimack Station could emit 
constantly at the mass-based emission value for each of those six hours 
and the area would attain the standard.
    Only one hour had emissions above the critical emission value of 
2,544 lb/hour. Specifically, Merrimack emitted 2,578.6 pounds of 
SO2 on December 1, 2015 during the 7 a.m. hour.
    EPA does not regard the single hour on December 1, 2015 at 7 a.m., 
during which Merrimack Station had emissions over the critical emission 
value, by itself as representing a serious risk for causing a violation 
of the NAAQS. EPA has previously acknowledged that there could possibly 
be hourly emission levels above the critical emission value from a 
source complying with a longer-term average emission limit, e.g., a 7-
day limit. As stated in the proposal, an hour where emissions are above 
the critical emission value does not necessarily mean that a NAAQS 
exceedance is occurring in that hour. Similarly, an individual hour 
where emissions are above the level of the comparably stringent 7-day 
limit (0.39 lb/MMBtu in this instance) does not mean that an exceedance 
of the NAAQS is occurring in that hour, especially if the level of 
emissions is below the critical emission value. This notion also does 
not take into account the possible exceedances that would be expected 
with emissions always at the critical emission value that would 
otherwise be avoided because emissions are generally required to be 
lower (in this case, on average 27% lower). Based on this reasoning, 
EPA concludes that the risk of an exceedance for the one hour with 
emissions above the critical emission value of 2,544 lb/hour during 
4.75 years of emissions from Merrimack Station (from July 1, 2013 to 
March 31, 2018) does not suggest that a violation of the NAAQS is 
likely to have occurred.
    (5) Notwithstanding the explanations above regarding the 
appropriateness of omitting certain data points from considering NAAQS 
compliance, such emissions data, if they had actually been 
representative of real emissions, would have caused a violation of the 
permit conditions for Merrimack Station, if the 7-day permit limit had 
been in place at the time. EPA has evaluated the Merrimack Station 
emissions data for the period January 1, 2012 through March 31, 2017 in 
accordance with the 7-day average emission rate limit, both with and 
without the omission of data points flagged as calculated or substitute 
data.
    This evaluation found 27 periods during which the associated 7-day 
emission average would have violated the terms of the permit 
conditions, had those terms been in place at the time and assuming that 
all data points flagged as calculated or substitute data are actual 
emissions. Of the 27 7-day periods, 26 occurred in 2012, while the 
facility was still permitted to bypass the FGD system, a practice that 
is not permitted under the conditions of the September 2016 permit TP-
0189. Even by omitting data points flagged as calculated or substitute 
data, none of the 7-day emission averages associated with these 26 7-
day periods in 2012 would have met the 7-day emission limit, had it 
been in place at the time.
    The one remaining 7-day period ended on December 11, 2014, and the 
associated 7-day emission average of 0.419 lb/MMBtu would have exceeded 
the emission limit of 0.39 lb/MMBtu, if data points flagged as 
calculated or substitute data were treated as actual emissions. By 
omitting the calculated or substitute data from this time period, the 
7-day emission average ending on December 11, 2014 would have been 0.20 
lb/MMBtu, which would comply with the 7-day limit of 0.39 lb/MMBtu, had 
it been in place at the time.
    This finding contradicts the commenter's assertion that the ``over 
224'' individual hours with emissions purportedly higher than the 
critical emission rate would not have resulted in an exceedance of the 
7-day average limit. On the contrary, even if the emissions with 
reported emissions above the critical emission value did represent 
actual emissions, which EPA argues in the previous sections is 
incorrect, Merrimack Station would have been out of compliance with the 
7-day limit permit had it been in effect at the time.
    Therefore, based on the reasoning supplied in the sections above, 
EPA disagrees with the commenter that emissions data from Merrimack 
Station demonstrate the inadequacy of the 7-day emission limit imposed 
by the State. Rather, the data most representative of Merrimack 
Station's current and expected future emissions indicate that the 
facility, when complying with the applicable permit restrictions, is 
extremely unlikely to cause a violation of the SO2 NAAQS. 
The emissions data presented by the commenter are not representative of 
Merrimack Station's current and expected future emissions, and are 
therefore not appropriate for use in assessing NAAQS compliance in this 
case.
    EPA offers the following additional discussion to further respond 
directly regarding the sufficiency of an appropriately-calculated, 
longer-term average limit, up to 30-days, with comparable stringency to 
a 1-hour critical emission value, to provide for attainment of the 1-
hour NAAQS. EPA has conducted analyses to evaluate the extent to which 
longer-term average

[[Page 25930]]

limits that have been adjusted to have comparable stringency to 1-hour 
limits at the critical emission value provide for attainment. In brief, 
while a longer-term average limit as approved in this action will allow 
occasions when emissions exceed the critical emission value, the use of 
a lower limit (i.e., as adjusted downward) compensates by requiring 
most values to be lower than they are required to be with a 1-hour 
limit at the critical emission value. EPA expects that the net result 
for this action will be that the comparably stringent limit will 
provide a sufficient constraint on the frequency and magnitude of 
occurrences of elevated emissions such that this control strategy based 
on the comparably stringent limit will reasonably provide for 
attainment.
    As stated in appendix B of EPA's April 2014 guidance, the Agency 
acknowledges that even with an adjustment to provide comparable 
stringency, a source complying with a longer term average emission 
limit could possibly have hourly emissions which occasionally exceed 
the critical emission value. It is important to recognize that an hour 
where emissions are above the critical value does not necessarily mean 
that a NAAQS exceedance is occurring in that hour. EPA's April 2014 
guidance states that ``if periods of hourly emissions above the 
critical emission value are a rare occurrence at a source, these 
periods would be unlikely to have a significant impact on air quality, 
insofar as they would be very unlikely to occur repeatedly at the times 
when the meteorology is conducive for high ambient concentrations of 
SO2'' (p. 24).
    Exceedances of the SO2 NAAQS occur when emissions from 
relevant sources are sufficiently high on occasions when the 
meteorology is conducive for those emissions to cause elevated 
SO2 concentrations. An illustrative example would be a case 
in which a single source has a dominant impact on area concentrations, 
and the source only causes an exceedance at a particular location with 
light southwest winds with limited dispersion. In this example, the 
likelihood of an exceedance at that location will be a function of the 
likelihood of elevated emissions occurring during times of light 
southwest winds with limited dispersion. Stated more generally, the 
likelihood of an exceedance is a function of the likelihood of 
emissions being high when the meteorology is conducive for the source 
to cause an exceedance. By extension, the likelihood of a violation is 
a function of the likelihood of emissions being high on a sufficient 
number of times with meteorology conducive to having exceedances to 
have the average of the 99th percentile daily maximum values exceed the 
NAAQS. Viewed another way, the occasions when the meteorology is 
conducive for the source to cause an exceedance at a particular 
location are likely to be infrequent, and high concentrations are 
contingent on both emissions being sufficiently high and the 
meteorology being sufficiently conducive. The NAAQS itself is based on 
relatively rare occurrences, being based on the 99th percentile of 
daily maximum concentrations. Nevertheless, the point here is that the 
occurrence of high emissions will not cause an exceedance if it does 
not occur when meteorology is conducive to having an exceedance. 
Furthermore, a source with rare occurrences of high emissions and with 
much more frequent occurrences of moderate emissions is more likely to 
have moderate emissions on those occasions with meteorology conducive 
for exceedances, and the design value for the source may be more prone 
to reflect the moderate emissions than the high emissions.
    Thus, for a source complying with a limit using an averaging period 
of up to 30 days reflecting the downward adjustment generally 
recommended in EPA's April 2014 guidance, at issue is the likelihood 
that the source would have sufficiently high emissions on a sufficient 
fraction of the potential exceedance days to cause an SO2 
NAAQS violation. Although results will differ according to individual 
circumstances, EPA has presented illustrative analyses (see appendix B 
of EPA's April 2014 guidance) that indicate that suitably adjusted 
longer-term average limits can generally be expected to provide 
adequate confidence that the attainment plan will provide for 
attainment.
    Therefore, based on the reasoning presented above, EPA disagrees 
with the commenter about the over 224 hours with emissions purported to 
be higher than the critical emission rate, and concludes that the 
longer-term limit for Merrimack Station is not expected to lead to a 
greater risk of a future violation of the NAAQS.
    Comment 3: The commenter stated that New Hampshire's approach to 
develop a longer-term averaging period using an ``adjustment ratio'' is 
problematic.\6\ Specifically, the commenter posits that the period of 
time selected by the State (i.e., July 4, 2013 through March 30, 2015) 
is not representative of current or expected future operations at 
Merrimack Station. The commenter stated that the State did not disclose 
the nature of data corrections provided by the Merrimack Station's 
owner at the time PSNH in documentation accompanying the proposed 
permit for the facility. The commenter indicated that the nondisclosure 
regarding the nature of the corrections raises concerns about the 
accuracy of the State's analysis. For future operations, the commenter 
points to New Hampshire's projection of Merrimack Station's annual 
emissions for 2018 of 1,907 tons SO2, which is nearly double 
the annual emissions total of 1,044 tons SO2 for the 
facility in 2014. The commenter asserts that the time period selected 
for developing the adjustment factor is arbitrary and not 
representative of expected future operations, and that therefore the 
State should have selected a different time period. The commenter 
identified ``significant spikes'' in hourly emissions in the months 
before or after the time period selected by the State that are not 
included in the State's emissions database. The commenter suggested 
that these emission ``spikes'' are inappropriately excluded, and as a 
result the State's results are likely to be skewed. The commenter 
provides several alternative adjustment factors based on different time 
periods that include periods with emission ``spikes,'' including an 
adjustment factor for each year from 2012 through 2015; the period of 
July 4, 2013 through March 30, 2015, used by the State in its analysis; 
and the 25-month period from March 1, 2013 through March 30, 2015. The 
alternative adjustment factors for these periods vary from 0.34 to 
0.90, which would result in associated 7-day limits of between 0.19 to 
0.48 lb/MMBtu. The commenter states that selecting the wrong time 
period for analysis can result in a more than doubling of the resulting 
emission rate. The commenter concludes that the methodology New 
Hampshire used for developing a 7-day emission rate is inadequate 
because the adjustment factor depends greatly on which temporal series 
of emissions data is examined.
---------------------------------------------------------------------------

    \6\ EPA terms these ratio values ``adjustment factors.''
---------------------------------------------------------------------------

    Response 3: EPA analyzed the commenter's assertion regarding 
variability in adjustment factors based on the time period selected. An 
adjustment factor is a value multiplied by the 1-hour critical emission 
value (i.e., the maximum 1-hour emission value established to be 
protective of the NAAQS) to determine a downwardly adjusted longer-term 
average limit for an emission unit at a level that EPA would expect to 
be comparably stringent to a

[[Page 25931]]

1-hour limit set at the critical emission value.
    As stated in EPA's April 2014 guidance, we expect that establishing 
an appropriate longer-term average limit will involve assessing a 
downward adjustment in the level of the limit that would provide for 
comparable stringency. This assessment should generally be conducted 
using data obtained by CEMS, in order to have sufficient data to obtain 
a robust and reliable assessment of the anticipated relationship 
between longer-term average emissions and 1-hour emission values. This 
is necessary to have a suitable assessment of the warranted degree of 
adjustment of the longer-term average limit in order to provide 
comparable stringency to the 1-hour emission rate that is determined to 
provide for attainment. EPA generally expects that datasets reflecting 
hourly data for at least 3 to 5 years of stable operation (i.e., 
without changes that significantly alter emissions variability) would 
be needed to conduct a suitably reliable analysis.
    For Merrimack Station, at the time that New Hampshire had conducted 
its analysis, only approximately 21 months of emissions data were 
available that were consistent with anticipated current and future 
operations. Specifically, the emissions units at Merrimack Station 
became subject to certain enforceable conditions contained in permit 
number TP-0008 beginning on July 1, 2013. Thus, emissions from 
Merrimack Station prior to July 1, 2013 are not expected to have an 
emissions profile consistent with the current and anticipated future 
emissions profile for those units. March 2015 was selected by the State 
as the end point of the emissions dataset because it was the last month 
in which data were available through AMPD at the time it conducted the 
analysis. During the period assessed by the State, the combined 
emissions from Merrimack Station's units MK1 and MK2 were always 
controlled by FGD and the dataset includes emissions representative of 
current and expected future typical operations, including startup and 
shutdown events. Because the dataset includes only data from Merrimack 
Station while using the control technology, it is appropriate for use 
in developing adjustment factors for emission limits at this facility. 
EPA has concluded that New Hampshire used data from an appropriate time 
period.
    Prior to deriving the adjustment factor, the State removed several 
data points from the AMPD dataset based on information provided by the 
facility. A justification for removal of these data points was included 
in the State's response to comments document to permit TP-0189 
(included in New Hampshire's Finding of Fact document), which was also 
included in the State's SIP submittal. Specifically, New Hampshire 
justified the removal of several data points because of quality 
assurance issues. The State indicated in its response to comments 
document that substitute data was included within the AMPD dataset for 
hours with emissions at levels the CEMS had not been appropriately 
maintained and quality assured to measure. The State indicated and EPA 
agrees that these substitute emission data are not representative of 
actual emissions. According to the State's SIP submittal, the 
SO2 dual span analyzer in the CEMS was adjusted as of 
February 4, 2015, to better characterize both lower- and higher-end 
emissions. In its response to comments, the State provided an hour-by-
hour listing of the omitted data points, and a detailed discussion of 
the reasoning for these omissions. The State's Findings of Fact 
document is included in the docket for this action. As such, EPA notes 
that New Hampshire sufficiently provided its rationale and approach for 
removing certain data points from the AMPD dataset in the State's 
response to comments document. Therefore, EPA concludes that the State 
has appropriately disclosed the nature of the data corrections in the 
State's SIP submittal, and that the public has had adequate notice and 
opportunity to comment on the State's justification for data removal in 
the current rulemaking process. EPA has placed the raw data that New 
Hampshire used in the docket for this action, but EPA asserts that the 
information provided by the State and by EPA in its proposal was 
adequate to clarify EPA's rationale for concurring with the State's 
analysis of the data.
    Regarding the omission of calculated or substitute data, the 
calculated or substitute data points are not reliable indicators of 
emissions during those hours and are not appropriate for inclusion in 
the calculation of the adjustment factor. Based on this reasoning, EPA 
considers the State's omission of these values in the calculation of 
the adjustment factor to be appropriate.
    The adjustment factor was calculated as the ratio of the 99th 
percentile of mass emissions for the 7-day average period to the 99th 
percentile of 1-hour mass emissions. For the rolling 7-day averaging 
period, the adjustment factor was 0.73. That is, using EPA's 
recommended approach for determining comparably stringent limits, the 
7-day mass emission rate limit would need to be 0.73 times (or 27% 
lower than) the critical emission value to have stringency comparable 
to a 1-hour limit at the critical emission value. The State multiplied 
its adjustment factor of 0.73 to the critical emission rate of 0.54 lb/
MMBtu to derive a comparably stringent emission rate of 0.39 lb/MMBtu. 
EPA has confirmed that the State appropriately implemented the 
recommended methodology for developing an adjustment factor based on 
the State's supplied dataset. EPA notes that this emission database 
does include hours representative of startup and shutdown conditions, 
as well as hours with elevated emissions or ``spikes.''
    There were five individual alternative adjustment factors for 
Merrimack Station presented by the commenter as evidence that EPA's 
methodology (including adjustment factors) is not appropriate for 
developing emissions limitations based on averaging times for periods 
up to 30 days. Four of the five alternative adjustment factors 
presented by the commenter are based upon only one year of emissions 
data for each of the annual periods of 2012 through 2015. One of the 
periods presented includes emissions over a period of 25 months, 
specifically for the period from March 2013 through March 2015 
resulting in an alternative adjustment factor of 0.47, compared to the 
State's adjustment factor of 0.73 based on the 21-month time period of 
July 2013 through March 2015. None of the alternative adjustment 
factors provided by the commenter were calculated in accordance with 
the recommendations contained in EPA's April 2014 guidance. 
Specifically, EPA stated in its April 2014 guidance ``that data sets 
reflecting hourly data for at least 3 to 5 years of stable operation 
(i.e., without changes that significantly alter emissions variability) 
would be needed to obtain a suitably reliable analysis'' (p. 30). 
Furthermore, the alternative adjustment factors for March 2013 through 
March 2015 and the annual periods for 2012 and 2013 as presented by the 
commenter include periods of time (i.e., those prior to July 1, 2013 
when FGD use was not an enforceable State permit condition) during 
which operations are not representative of current and expected future 
operations at Merrimack Station, as discussed in greater detail in our 
response to Comment 2 of the notice. The remaining alternative 
adjustment factors that do not contain periods of time prior to July 1, 
2013, i.e., the annual periods for 2014 and 2015, are 0.90 and 0.70, 
respectively, which are reasonably consistent with the State's finding 
based

[[Page 25932]]

on a larger dataset. However, the commenter's results illustrate a 
point that EPA considered in formulating its guidance, which is that 
using insufficient data, e.g., using only one year's data, is prone to 
yield results that vary unduly by data period and may not be a 
sufficiently robust basis for determining a reliable adjustment factor. 
The variability of these annual values demonstrates the insufficiency 
of the annual time period for use in development of such an adjustment 
factor, but does not demonstrate the insufficiency of the method 
contained within EPA's April 2014 guidance had it been appropriately 
applied, nor does it demonstrate that New Hampshire's adjustment factor 
is inappropriate.
    EPA recognizes that the State used 21 months in its emissions 
variability analysis instead of the 3 to 5 years recommended for use in 
EPA's April 2014 guidance. As such, EPA has evaluated whether the 
period used by the State results in an appropriate adjustment factor. 
Specifically, EPA compared the State's adjustment factor to EPA's 
average 30-day adjustment factor for comparable sources. Merrimack 
Station's FGD system employs a wet scrubber, and so EPA compared New 
Hampshire's adjustment factor to the average adjustment factors listed 
in appendix D of the April 2014 guidance for sources with wet scrubbers 
(derived from a database of 210 sources). For this set of sources, EPA 
calculated an average adjustment factor for 30-day average limits of 
0.71 and an average adjustment factor for 24-hour limits of 0.89. The 
comparison of New Hampshire's adjustment factor of 0.73 for a 7-day 
limit for Merrimack Station suggests that the 21 months of data at 
Merrimack Station have variability that is quite similar to that of 
other similar facilities in the United States. Based on this 
comparison, EPA concludes that the State's adjustment factor is 
reasonable and will result in an appropriate downward adjustment from 
the critical emission value.
    Based on the State's SIP submittal, New Hampshire's future 
projection of SO2 emissions at Merrimack Station to 2018 
indicates an increase of nearly 85% compared to 2014 emissions for the 
facility. Specifically, Tables 5-1B and 5-2B of the State's SIP 
submittal indicate that Merrimack Station's SO2 emissions 
were 1,044 tons in 2014 and are projected to be 1,927 tons in 2018. The 
emission projection for 2018 includes the caveat from the State that it 
relies on an assumed control efficiency for the FGD of 90%, which is 
less efficient than the updated control efficiency of 94% for the FGD 
included in the State's SIP submittal. Nevertheless, this projected 
increase in annual emissions does not, however, indicate a different 
emissions profile. That is, based on available information, EPA does 
not expect an increase in the variability of hourly emissions due to an 
increase in annual emissions. In fact, the attainment demonstration 
included in New Hampshire's SIP submittal indicates that annual 
SO2 emissions at the critical emission value, equivalent to 
annual emissions of 11,144 tons, is anticipated to be protective of the 
2010 SO2 NAAQS. The State's comparably stringent 7-day 
average limit of 0.39 lb/MMBtu equates to total annual SO2 
emissions of 8,047 tons. Both values are above the State's 2018 
projected emissions of 1,927 tons. Because New Hampshire's attainment 
demonstration shows that the critical emission value is protective of 
the NAAQS, and the State's 7-day limit is comparably stringent to the 
1-hour critical emission value, EPA concludes that the State's 
projected 85% increase in annual SO2 emissions from 2014 to 
2018 would not result in a violation of the NAAQS.
    Therefore, based on the reasoning presented above, EPA has 
concluded that the commenter has not demonstrated that the State 
developed its adjustment factor for Merrimack Station inappropriately, 
or that the State's 7-day limit for Merrimack Station derived using the 
adjustment factor is inadequate.
    Comment 4: The commenter indicates that the polar receptor grid 
used by the State in its modeling analysis is inadequate because of the 
small overall number of receptors and lack of coverage over large areas 
of land. The commenter states that the polar grid ensures that the 
model will underpredict concentrations due to these ``blind spots,'' 
areas where there are no receptors and which the model will overlook 
when the wind is blowing in their direction across the sources. Because 
the model is ultimately the basis for the development of the emissions 
limit for Merrimack Station, the commenter posits that the polar 
receptor grid with contiguous radial coverage gaps is improper.
    Response 4: EPA agrees with the commenter that simple polar grids 
alone may not be appropriate for use without refinement in refined 
modeling analyses, though inclusion of a polar receptor grid does not 
in and of itself disqualify an attainment demonstration.
    Receptors are points that represent physical locations at which the 
air dispersion models will predict ambient pollutant concentrations. 
Groups of Cartesian or polar receptors usually are defined as a 
receptor grid network or grid. The primary purpose of this network or 
grid is to locate the maximum impact of concern per pollutant and 
averaging period. Deciding which type to use is largely a function of 
the type of modeling being performed (screening or refined), the size 
and number of emission sources, or the site location (including 
topography), and should be selected to provide the best ``coverage'' 
for the facility being modeled. Two types of receptors are generally 
employed: (1) A Cartesian receptor grid, which consists of receptors 
identified by their x (east-west) and y (north-south) coordinates; and 
(2) a polar receptor grid that consists of receptors identified by 
their distance and direction (angle) from a user defined origin (e.g., 
main boiler stack). Discrete receptors are used to identify specific 
locations of interest (e.g., school, community building). A modeling 
receptor grid may consist of any combination of discrete, polar, or 
Cartesian receptors, but must provide sufficient detail and resolution 
to identify the maximum impact.
    On October 30, 2015, the State submitted preliminary modeling to 
EPA for the attainment demonstration for the Central New Hampshire 
Nonattainment Area. EPA responded on January 6, 2016, to the State's 
preliminary modeling submittal. In EPA's response, the Agency indicated 
that section 4.2.1.2(b) of the Guideline \7\ describes the process for 
performing screening modeling in areas with complex terrain. As stated 
in our letter, in areas with complex terrain, ``even relatively small 
changes in a receptor's location may substantially affect the predicted 
concentration.'' The Guideline recommended a dense array of receptors 
in those situations, and suggests two modeling runs: the first with ``a 
moderate number of receptors carefully located over the area of 
interest,'' and a second with ``a more dense array of receptors in 
areas showing potential for high concentrations, as indicated by the 
results of the first model run.'' This process is also consistent with 
section 7.2.2 (Critical Receptor Sites) of the Guideline, which states 
that ``selection of receptor sites should be a case-by-case 
determination taking into consideration the topography, the 
climatology, monitor sites, and the results of the initial screening 
procedure.'' In our letter to New

[[Page 25933]]

Hampshire, EPA noted that the preliminary modeling results (i.e., those 
presented to the Agency on October 30, 2015) showed maximum 
concentrations resulting from Merrimack Station's SO2 
emissions in areas of complex terrain between 9 to 13 kilometers from 
Merrimack Station. EPA stated that the polar receptor grid at those 
distances from the source were insufficiently dense to properly 
characterize the extent of the impacts at locations with complex 
terrain. For example, at 13 kilometers from the source, the lateral 
distance between receptors is greater than 2 kilometers. EPA also 
indicated that other locations with similar terrain characteristics in 
the same general distance (i.e., 9-13 kilometers) from Merrimack 
Station did not have adequate receptor coverage. To address this issue, 
EPA suggested in its January 6, 2016 letter, that New Hampshire perform 
refined modeling consistent with its existing protocol, but with a 
denser array of receptors in the areas shown in the preliminary 
modeling to have the potential for high concentrations. Specifically, 
areas of complex terrain at distances within 15 kilometers of Merrimack 
Station, and particularly such areas to the northeast, were suggested 
by EPA to be modeled with high resolution receptor grids. EPA listed 
these areas and provided a map of these areas to the State. EPA 
indicated that these terrain features have the potential to be highly 
impacted by Merrimack Station because of their geographic 
characteristics and locations, but were not well characterized by the 
preliminary modeling due to the sparseness of the polar grid at 
distances beyond around 5 kilometers.
---------------------------------------------------------------------------

    \7\ At the time of EPA's January 6, 2016 letter to New 
Hampshire, the update to the Guideline had not yet been finalized 
and was not in effect. Therefore, the applicable Guideline was the 
version published on November 9, 2005 (see 70 FR 68218).
---------------------------------------------------------------------------

    In response to EPA's January 2016, letter, the State included 
additional receptors in these areas for its refined modeling conducted 
in February 2016. Specifically, New Hampshire included 2,308 additional 
receptors in dense Cartesian arrays with 100-meter spatial resolution 
over the areas of expected maximum predicted concentrations based on 
preliminary modeling, including over the areas suggested by EPA within 
5-15 kilometers from Merrimack Station. After reviewing the receptor 
grid included by the State in its refined modeling, EPA concludes that 
areas of complex terrain within 15 kilometers have adequate coverage to 
identify potential impacts in those areas. This conclusion is 
consistent with the statement in section 4 (Models for Carbon Monoxide, 
Lead, Sulfur Dioxide, Nitrogen Dioxide and Primary Particulate Matter) 
of the Guideline (specifically section 4.2(a)) that ``[i]n most cases, 
maximum source impacts of inert pollutants will occur within the first 
10 to 20 km from the source.'' Furthermore, EPA's review of both the 
preliminary and refined modeling indicate that these areas of complex 
terrain are likely to include the highest impact area. Therefore, EPA 
finds that the modeling domain and receptor network are sufficient to 
identify maximum impacts from Merrimack Station, and are therefore 
adequate for characterizing the nonattainment area.
    Comment 5: The commenter pointed out an error in Table 3-1 of the 
State's draft SIP submittal. Specifically, the commenter indicated that 
Table 3-1 incorrectly showed areas that are undesignated in New 
Hampshire as being designated Unclassifiable. The commenter indicated 
that those areas should instead be identified as undesignated.
    Response 5: EPA agrees with the commenter that all areas in New 
Hampshire other than the Central New Hampshire Nonattainment Area were 
undesignated as of the date of New Hampshire's submittal (i.e., January 
31, 2017). In its response to this identical comment on its proposed 
SIP submittal, the State indicated that Table 3-1 had been corrected. 
EPA has verified that the State did indeed correct the table. EPA notes 
that revised recommendations from New Hampshire other than those listed 
in Table 3-1 were received by EPA in December 2016, specifically for 
attainment at the New Hampshire Seacoast area and attainment/
unclassifiable for all other previously undesignated areas. 
Furthermore, on January 9, 2018, EPA published a document of a final 
rule that designated all areas in New Hampshire other than the Central 
New Hampshire Nonattainment Area as attainment/unclassifiable (see 83 
FR 1098, 1143, to be codified at 40 CFR 81.330). These inconsistencies 
in Table 3-1 with subsequent occurrences have to do with the timing of 
the SIP submittal along with the December 2016 update to the State's 
recommendations and EPA's January 9, 2018 final designations. These 
inconsistencies do not affect EPA's view of whether New Hampshire has 
satisfied applicable nonattainment planning requirements.
    Comment 6: The commenter states that the State's SIP submittal 
incorrectly indicates that an attainment demonstration can be made 
based on monitor readings alone. This idea is contrary to other 
statements in the State's SIP submittal, and also to EPA's April 2014 
guidance, which states that monitor data alone is insufficient for an 
attainment demonstration, and that modeling analyses are also required. 
The commenter asserts that the statement should be removed from the 
State's SIP submittal.
    Response 6: The State indicated in its response to an identical 
comment on its draft SIP submittal that it planned to remove the phrase 
``and thus may be able to demonstrate attainment for the SO2 
NAAQS'' from Section 3.1.1 on page 9 of its SIP submittal. In doing so, 
the State would be satisfying the request made by the commenter. 
However, the erroneous phrase still appeared in the State's January 31, 
2017 SIP submittal to EPA. EPA agrees with the commenter that the 
phrase is incorrect and ought not to be in the plan. EPA communicated 
with the State to confirm that it had intended to remove the phrase as 
indicated by the State's response to comments on its draft SIP 
submittal, and to suggest a clarification. On November 29, 2017, New 
Hampshire sent EPA a letter indicating that the language had been 
erroneously included in its January 31, 2017 submittal, and providing a 
corrected page 9 of the State's SIP submittal. EPA considers this 
amended version (i.e., the January 31, 2017, submittal as amended by 
the November 29, 2017, correction on page 9) to be consistent with the 
State's record, as included in its response to comments.
    Comment 7: The commenter identifies an error in Table 5-1B of the 
State's draft SIP submittal. Specifically, the commenter indicates that 
the table erroneously states that the total estimated emissions for the 
Central New Hampshire Nonattainment Area for 2014 was 22,947 tons of 
SO2. The commenter further states that the proper total for 
2014 emissions should be 1,480 tons of SO2. The commenter 
indicates that the figure is assumed to be an error that should be 
corrected.
    Response 7: EPA agrees with the commenter that the total 2014 
emissions within the Central New Hampshire Nonattainment Area should be 
1,480 tons SO2. The commenter had supplied an identical 
comment on New Hampshire's draft SIP submittal, and the State's 
response to comment document included in its final SIP submittal stated 
that the error would be corrected. As indicated by the State in its 
response to comments, Table 5-1B shows the corrected value. As such, 
EPA considers this comment to have been already addressed by the State.
    Comment 8: In the incorporated comments dated July 15, 2016, the 
commenter states that New Hampshire is long overdue for finalizing a 
plan to ensure attainment and maintenance of the SO2 NAAQS. 
The commenter goes

[[Page 25934]]

on to state that the (then) proposed permit is apparently only a step 
towards developing such a SIP. The commenter concludes by urging the 
State to swiftly address the issues identified in its comments on the 
proposed permit for Merrimack Station.
    Response 8: There are two plausible interpretations of this 
comment. The first interpretation is procedural. Interpreted in this 
fashion, the commenter would be requesting that the permitting 
authority expedite the permitting for Merrimack Station, which would be 
a critical component of the anticipated attainment plan for the area 
around Merrimack Station. Interpreted this first way, the comment is 
addressed through the current action, which is the final step in the 
procedure for approving an attainment plan for the area. A second 
interpretation implies technical insufficiency. Interpreted in this 
fashion, the commenter would be indicating that the proposed permit, 
when finalized, would be just one of multiple required actions 
necessary to ensure attainment in the nonattainment area. Interpreted 
this second way, the comment rests on the previous arguments provided 
by the commenter suggesting that the State's proposed plan does not 
ensure attainment of the NAAQS. On these grounds, EPA disagrees with 
the commenter that the proposed nonattainment area plan may be 
insufficient to ensure attainment. EPA has provided ample discussion 
and evidence, in both the current response to comments and the 
September 28, 2017 proposal, for why the State's nonattainment plan and 
SO2 attainment demonstration are sufficient.

III. Final Action

    EPA has determined that New Hampshire's SO2 
nonattainment plan meets the applicable requirements of sections 110, 
172, 191, and 192 of the CAA. EPA is approving New Hampshire's January 
31, 2017 SIP submission, as amended by the State on November 29, 2017, 
for attaining the 2010 primary 1-hour SO2 NAAQS for the 
Central New Hampshire Nonattainment Area and for meeting other 
nonattainment area planning requirements. This SO2 
nonattainment plan includes New Hampshire's attainment demonstration 
for the SO2 nonattainment area. The nonattainment area plan 
also addresses requirements for RFP, RACT/RACM, enforceable emission 
limits and control measures, base-year and projection-year emission 
inventories, and contingency measures.
    In New Hampshire's SIP submittal to EPA, New Hampshire included the 
applicable monitoring, testing, recordkeeping, and reporting 
requirements contained in Merrimack Station's permit, TP-0189, to 
demonstrate how compliance with Merrimack Station's SO2 
emission limit will be achieved and determined. EPA is approving into 
the New Hampshire SIP the provisions of Merrimack Station's permit, TP-
0189, that constitute the SO2 operating and emission limits 
and their associated monitoring, testing, recordkeeping, and reporting 
requirements. EPA is approving these provisions into the State's SIP 
through incorporation by reference, as described in section IV., below.
    EPA is not removing the portion of the New Hampshire SIP entitled 
``EPA-approved State Source specific requirements'' as it pertains to 
Merrimack Station's July 2011 permit, TP-0008, because EPA did not 
receive a request from the State to do so. See 40 CFR 52.1520(d). 
However, EPA considers those provisions to be superseded by the 
conditions of TP-0189, which are more stringent, and which are being 
incorporated into the SIP in this final action. Specifically, two of 
the provisions, items 6 and 8 from Table 4, relate to SO2 
emissions limits that have been superseded by Merrimack Station's 
September 2016 permit, TP-0189. Item 10 from Table 4 has also been 
superseded by Merrimack Station's September 2016 permit, TP-0189, in 
that the existing SIP provision allowed operation of one of Merrimack 
Station's two boilers, MK1, for up to 840 hours in any consecutive 12-
month period through the emergency bypass stack, i.e., not through the 
FGD system. Each of the corresponding provisions of Merrimack Station's 
September 2016 permit, TP-0189, are more stringent than those existing 
SIP provisions. The limits EPA is approving into New Hampshire's SIP in 
this action do not exempt any hours from being subject to the limit.

IV. Incorporation by Reference

    In this rule, EPA is finalizing regulatory text that includes 
incorporation by reference. In accordance with requirements of 1 CFR 
51.5, EPA is finalizing the incorporation by reference of certain 
federally enforceable provisions of Merrimack Station's permit, TP-
0189, effective on September 1, 2016, described in the amendments to 40 
CFR part 52 set forth below. Specifically, the following provisions of 
that permit are incorporated by reference: Items 1, 2, and 3 in Table 4 
(``Operating and Emission Limits''); items 1 and 2 in Table 5 
(``Monitoring and Testing Requirements''); items 1 and 2 in Table 6 
(``Recordkeeping Requirements''); and items 1 and 2 in Table 7 
(``Reporting Requirements''). EPA has made, and will continue to make, 
relevant documents, including the portions of TP-0189 being 
incorporated by reference, generally available through 
www.regulations.gov.

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this action merely approves state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this action:

     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using

[[Page 25935]]

practicable and legally permissible methods, under Executive Order 
12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction. In those areas of Indian 
country, the rule does not have tribal implications and will not impose 
substantial direct costs on tribal governments or preempt tribal law as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this action and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by August 6, 2018. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this action for the purposes of 
judicial review nor does it extend the time within which a petition for 
judicial review may be filed, and shall not postpone the effectiveness 
of such rule or action. This action may not be challenged later in 
proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Reporting and recordkeeping 
requirements, Sulfur oxides.

    Dated: May 23, 2018.
Alexandra Dunn,
Regional Administrator, EPA New England.

    Part 52 of chapter I, title 40 of the Code of Federal Regulations 
is amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart EE--New Hampshire

0
2. Section 52.1520 is amended:
0
 a. In the table in paragraph (d) by:
0
 i. Revising the entry for ``PSNH Merrimack Station''; and
0
 ii. Adding the entry for ``PSNH d/b/a Eversource Energy Merrimack 
Station,'' at the end of the table; and
0
b. In the table in paragraph (e), by adding an entry for ``Central New 
Hampshire Nonattainment Area Plan for the 2010 Primary 1-Hour Sulfur 
Dioxide NAAQS'' at the end of the table.
    The revision and additions read as follows:


Sec.  52.1520   Identification of plan.

* * * * *
    (d) * * *

                             EPA-Approved New Hampshire Source Specific Requirements
----------------------------------------------------------------------------------------------------------------
                                                         State
          Name of source               Permit No.      effective    EPA approval date   Additional explanations/
                                                          date             \2\           Sec.   52.1535 citation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
PSNH Merrimack Station...........  TP-0008..........     7/8/2011  8/22/2012, 77 FR     Flue Gas Desulfurization
                                                                    50602.               System. Portions of
                                                                                         this permit have been
                                                                                         superseded by TP-0189
                                                                                         for PSNH d/b/a
                                                                                         Eversource Energy
                                                                                         Merrimack Station.
 
                                                  * * * * * * *
PSNH d/b/a Eversource Energy       TP-0189..........     9/1/2016  6/5/2018, [Insert    Items 1, 2, and 3 in
 Merrimack Station.                                                 Federal Register     Table 4 ``Operating and
                                                                    citation].           Emission Limits'';
                                                                                         items 1 and 2 in Table
                                                                                         5 ``Monitoring and
                                                                                         Testing Requirements'';
                                                                                         items 1 and 2 in Table
                                                                                         6 ``Recordkeeping
                                                                                         Requirements''; items 1
                                                                                         and 2 in Table 7
                                                                                         ``Reporting
                                                                                         Requirements''.
----------------------------------------------------------------------------------------------------------------
\2\ In order to determine the EPA effective date for a specific provision listed in this table, consult the
  Federal Register notice cited in this column for the particular provision.

    (e) * * *

                                           New Hampshire Nonregulatory
----------------------------------------------------------------------------------------------------------------
                                  Applicable
  Name of  nonregulatory SIP     geographic or    State submittal     EPA approved
          provision              nonattainment     date/effective       date \ 3\            Explanations
                                     area               date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Central New Hampshire          Central New               1/31/2017  6/5/2018 [Insert  ..........................
 Nonattainment Area Plan for    Hampshire SO2                        Federal
 the 2010 Primary 1-Hour        Nonattainment                        Register
 Sulfur Dioxide NAAQS.          Area.                                citation].
----------------------------------------------------------------------------------------------------------------
\3\ In order to determine the EPA effective date for a specific provision listed in this table, consult the
  Federal Register notice cited in this column for the particular provision.


[[Page 25936]]

[FR Doc. 2018-11597 Filed 6-4-18; 8:45 am]
BILLING CODE 6560-50-P



                                           25922               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                                       EPA APPROVED NONREGULATORY PROVISIONS AND QUASI-REGULATORY MEASURES IN THE TEXAS SIP
                                                                                   Applicable          State
                                                                                 geographic or       submittal/
                                              Name of SIP provision                                                      EPA approval date                                   Comments
                                                                                 nonattainment        effective
                                                                                     area               date


                                                     *                       *                        *                       *                       *                        *                      *
                                           Infrastructure and Interstate     Statewide ........      12/01/2015       6/5/2018, [Insert Federal      Approval for CAA elements 110(a)(2)(A), (B), (C),
                                              Transport for the 2012                                                    Register citation].             (D)(i)(I), (D)(i)(II) (portion pertaining to PSD),
                                              PM2.5 NAAQS.                                                                                              (D)(ii), (E), (F), (G), (H), (J), (K), (L), and (M). 6/5/
                                                                                                                                                        2018, [Insert Federal Register citation].



                                           [FR Doc. 2018–11973 Filed 6–4–18; 8:45 am]               This action is being taken in accordance                I. Background and Purpose
                                           BILLING CODE 6560–50–P                                   with the CAA.                                              On June 22, 2010, EPA promulgated a
                                                                                                    DATES:   This rule is effective on July 5,              new 1-hour primary SO2 NAAQS of 75
                                                                                                    2018.                                                   parts per billion (ppb), which is met at
                                           ENVIRONMENTAL PROTECTION                                                                                         an ambient air quality monitoring site
                                           AGENCY                                                   ADDRESSES:    EPA has established a                     when the 3-year average of the annual
                                                                                                    docket for this action under Docket                     99th percentile of daily maximum 1-
                                           40 CFR Part 52                                           Identification No. EPA–R01–OAR–                         hour concentrations does not exceed 75
                                                                                                    2017–0083. All documents in the docket                  ppb, as determined in accordance with
                                           [EPA–R01–OAR–2017–0083; FRL–9978–                        are listed on the www.regulations.gov                   appendix T of 40 CFR part 50. See 75
                                           27—Region 1]                                             website. Although listed in the index,                  FR 35520, codified at 40 CFR 50.17(a)
                                                                                                    some information is not publicly                        and (b). On August 5, 2013, EPA
                                           Air Plan Approval; New Hampshire;                        available, i.e., CBI or other information
                                           Nonattainment Plan for the Central                                                                               designated a first set of 29 areas of the
                                                                                                    whose disclosure is restricted by statute.              country as nonattainment for the 2010
                                           New Hampshire Sulfur Dioxide                             Certain other material, such as
                                           Nonattainment Area                                                                                               SO2 NAAQS, including the Central New
                                                                                                    copyrighted material, is not placed on                  Hampshire Nonattainment Area within
                                           AGENCY:  Environmental Protection                        the internet and will be publicly                       the State of New Hampshire. See 78 FR
                                           Agency (EPA).                                            available only in hard copy form.                       47191, codified at 40 CFR part 81,
                                                                                                    Publicly available docket materials are                 subpart C. These ‘‘round one’’ area
                                           ACTION: Final rule.
                                                                                                    available at www.regulations.gov or at                  designations were effective October 4,
                                           SUMMARY:   The Environmental Protection                  the U.S. Environmental Protection                       2013. Section 191(a) of the CAA directs
                                           Agency (EPA) is approving the State                      Agency, EPA New England Regional                        states to submit SIPs for areas
                                           Implementation Plan (SIP) revision that                  Office, Office of Ecosystem Protection,                 designated as nonattainment for the SO2
                                           the State of New Hampshire submitted                     Air Permits Toxics and Indoor Programs                  NAAQS to EPA within 18 months of the
                                           to EPA on January 31, 2017, for                          Unit, 5 Post Office Square—Suite 100,                   effective date of the designation, i.e., by
                                           attaining the 1-hour sulfur dioxide (SO2)                Boston, MA. EPA requests that if at all                 no later than April 4, 2015 in this case.
                                           primary national ambient air quality                     possible, you contact the contact listed                These SIPs are required to demonstrate
                                           standard (NAAQS) for the Central New                     in the FOR FURTHER INFORMATION                          that their respective areas will attain the
                                           Hampshire Nonattainment Area. This                       CONTACT section to schedule your                        NAAQS as expeditiously as practicable,
                                           plan (herein called a ‘‘nonattainment                    inspection. The Regional Office’s                       but no later than 5 years from the
                                           plan’’) includes New Hampshire’s                         official hours of business are Monday                   effective date of designation, which is
                                           attainment demonstration and other                       through Friday, 8:30 a.m. to 4:30 p.m.,                 October 4, 2018, in accordance with
                                           elements required under the Clean Air                    excluding legal holidays.                               CAA sections 191–192.
                                           Act (CAA). In addition to an attainment                  FOR FURTHER INFORMATION CONTACT:                           Section 192(a) requires that such
                                           demonstration, the nonattainment plan                    Leiran Biton, Air Permits, Toxics, and                  plans shall provide for NAAQS
                                           addresses the requirements for meeting                   Indoor Programs Unit, U.S.                              attainment as expeditiously as
                                           reasonable further progress (RFP)                        Environmental Protection Agency, EPA                    practicable, but no later than 5 years
                                           toward attainment of the NAAQS,                          New England Regional Office, 5 Post                     from the effective date of the
                                           implementation of reasonably available                   Office Square—Suite 100, (Mail code                     nonattainment designation. Section
                                           control measures and reasonably                          OEP05–2), Boston, MA 02109–3912, tel.                   172(c) of part D of the CAA lists the
                                           available control technology (RACM/                      (617) 918–1267, email biton.leiran@                     required components of a
                                           RACT), base-year and projection-year                     epa.gov.                                                nonattainment plan submittal. The base
                                           emission inventories, enforceable                                                                                year emissions inventory (section
                                           emissions limitations and control                        SUPPLEMENTARY INFORMATION:                              172(c)(3)) is required to show a
                                           measures, and contingency measures.                      Throughout this document whenever                       ‘‘comprehensive, accurate, current
                                           EPA concludes that New Hampshire has                     ‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean             inventory’’ of all relevant pollutants in
                                           appropriately demonstrated that the                      EPA.                                                    the nonattainment area. The
                                           nonattainment plan provisions provide                                                                            nonattainment plan must identify and
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                                           for attainment of the 2010 1-hour                        Table of Contents                                       quantify any expected emissions from
                                           primary SO2 NAAQS in the Central New                     I. Background and Purpose                               the construction of new sources to
                                           Hampshire Nonattainment Area by the                      II. Response to Comments                                account for emissions in the area that
                                           applicable attainment date and that the                  III. Final Action                                       might affect reasonable further progress
                                           nonattainment plan meets the other                       IV. Incorporation by Reference                          (RFP) toward attainment, or that might
                                           applicable requirements under the CAA.                   V. Statutory and Executive Order Reviews                interfere with attainment and


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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                          25923

                                           maintenance of the NAAQS, and it must                   Furthermore, with this current action                  October 30, 2017. EPA received a single
                                           provide for a nonattainment new source                  issuing final approval of New                          set of comments on the proposed
                                           review (NNSR) program (section                          Hampshire’s SIP submittal, EPA’s FIP                   approval of New Hampshire’s
                                           172(c)(5)). The attainment                              obligation no longer applies, and no FIP               nonattainment area plan for the Central
                                           demonstration must include a modeling                   will be imposed as a result of New                     New Hampshire Nonattainment Area.
                                           analysis showing that the enforceable                   Hampshire’s missing the deadline.                      The comments are available in the
                                           emissions limitations and other control                    On November 29, 2017, EPA received                  docket for this final rulemaking action.
                                           measures taken by the state will provide                a letter from New Hampshire correcting                 EPA’s summary of the comments and
                                           for RFP and expeditious attainment of                   a misstatement in its January 2017                     EPA’s responses are provided below.
                                           the NAAQS (section 172(c)(2), (4), (6),                 submittal to EPA. The State had earlier                For a comprehensive discussion of New
                                           and (7)). The nonattainment plan must                   intended to modify its January 2017                    Hampshire’s SIP submittal and EPA’s
                                           include an analysis and provide for                     submittal to EPA in response to a public               analysis and rationale for approval of
                                           implementation of the RACM                              comment on its draft nonattainment                     the State’s submittal and attainment
                                           considered, including RACT (section                     area plan, but inadvertently neglected to              demonstration for this area, please refer
                                           172(c)(1)). Finally, the nonattainment                  make the correction. Specifically, the                 to EPA’s September 28, 2017 notice of
                                           plan must provide for contingency                       State enclosed in its January 2017                     proposed rulemaking.
                                           measures (section 172(c)(9)) to be                      submittal to EPA all comments and                         The remainder of this preamble
                                           implemented either in the case that RFP                 responses to comments relating to its                  summarizes EPA’s final approval of
                                           toward attainment is not made, or in the                draft nonattainment area plan, and                     New Hampshire’s SIP submittal and
                                           case that the area fails to attain the                  among those was a set of comments                      attainment demonstration for the
                                           NAAQS by the attainment date.                           submitted by Sierra Club to the State on               Central New Hampshire Nonattainment
                                              On April 23, 2014, EPA issued a                      January 5, 2017. Among other                           Area and contains EPA’s response to
                                           guidance document entitled, ‘‘Guidance                  comments, Sierra Club asserted that the                public comments.
                                           for 1-Hour SO2 Nonattainment Area SIP                   draft nonattainment area plan
                                                                                                                                                          II. Response to Comments
                                           Submissions.’’ This guidance provides                   ‘‘incorrectly suggests that an attainment
                                           recommendations for the development                     demonstration can be made based on                        The single set of comments
                                           of SO2 nonattainment SIPs to satisfy                    monitor readings alone,’’ counter to                   addressing the proposed approval of the
                                           CAA requirements (see, e.g., sections                   EPA’s April 2014 guidance, and stated                  SIP revision for the Central New
                                           172, 191, and 192). An attainment                       that the plan should be revised to                     Hampshire Nonattainment Area was
                                           demonstration must also meet the                        remove this inconsistency. In its                      received from Sierra Club on October
                                           requirements of 40 CFR part 51,                         response to that comment, New                          30, 2017. The Sierra Club’s October 30,
                                           subparts F and G, and 40 CFR part 51,                   Hampshire indicated that it would                      2017 comments explicitly incorporated
                                           appendix W (the Guideline on Air                        remove the language per Sierra Club’s                  a July 15, 2016 comment letter with
                                           Quality Models; ‘‘the Guideline’’), and                 comment, but inadvertently included                    supporting attachments submitted to
                                           include inventory data, modeling                        the erroneous language nonetheless in                  New Hampshire by Sierra Club on
                                           results, and emissions reduction                        its January 2017 submittal to EPA. New                 behalf of both Sierra Club and
                                           analyses on which the state has based                   Hampshire’s November 29, 2017                          Conservation Law Foundation (CLF)
                                           its projected attainment. The guidance                  correction modifies the State’s original               regarding the State’s proposed permit
                                           also discusses criteria EPA expects to                  submittal to exclude the erroneous                     for Merrimack Station. Because the
                                           use in assessing whether emission limits                language identified by Sierra Club,                    October 30, 2017 Sierra Club comments
                                           with longer averaging times of up to 30                 consistent with the State’s response to                on EPA’s proposal are nearly identical
                                           days ensure attainment of the SO2                       comments. Hereafter, references to the                 to the prior July 15, 2016 comments,
                                           NAAQS.                                                  State’s January 31, 2017 SIP submittal                 except where the October 30, 2017
                                              For a number of areas, including the                 are intended to include the November                   comments provide updated information,
                                           Central New Hampshire Nonattainment                     29, 2017 correction.                                   EPA’s responses to the October 30, 2017
                                           Area, EPA published a document on                          On September 28, 2017 (82 FR 45242),                Sierra Club comments also serve to
                                           March 18, 2016, that pertinent states                   EPA proposed to approve New                            respond to issues raised in the July 15,
                                           had failed to submit the required SO2                   Hampshire’s January 31, 2017                           2016 comments to the State, except
                                           nonattainment plan by the submittal                     nonattainment plan submittal and SO2                   where EPA identifies discussion as
                                           deadline. See 81 FR 14736. This finding                 attainment demonstration. The State’s                  specifically applying only to comments
                                           initiated a deadline under CAA section                  submittal and attainment demonstration                 from July 15, 2016. In the following
                                           179(a) for the potential imposition of                  included all the specific attainment                   discussion, EPA will refer to the Sierra
                                           new source review and highway                           elements mentioned above, including                    Club or Sierra Club/CLF as ‘‘the
                                           funding sanctions, and for EPA to                       new SO2 emission limits found to be                    Commenter.’’ To review the complete
                                           promulgate a federal implementation                     comparably stringent to the 1-hour form                set of comments received, refer to the
                                           plan (FIP) under section 110(c) of the                  of the primary SO2 NAAQS and                           docket for this rulemaking as identified
                                           CAA. In response to the requirement for                 associated control technology efficiency               above. A summary of the comments
                                           SO2 nonattainment plan submittals,                      requirements for the electric generating               received and EPA’s responses are
                                           New Hampshire submitted a                               source Merrimack Station, currently                    provided below.
                                           nonattainment plan for the Central New                  owned and operated by GSP Merrimack                       Comment 1: The commenter asserted
                                           Hampshire Nonattainment Area on                         LLC and formerly by Public Service of                  that the proposed 7-day average limit on
                                           January 31, 2017. Pursuant to New                       New Hampshire (PSNH) d/b/a                             emissions from Merrimack Station is
                                           Hampshire’s January 31, 2017 submittal                  Eversource Energy, impacting the                       insufficient to protect the 1-hour
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                                           and EPA’s subsequent completeness                       Central New Hampshire Nonattainment                    NAAQS. The commenter indicated that
                                           determination letter dated March 20,                    Area. Merrimack Station’s new SO2                      short-term exposure to SO2 for as little
                                           2017, these sanctions under section                     emission limits were developed in                      as five minutes has significant health
                                           179(a) will not be imposed as a result                  accordance with EPA’s April 2014                       impacts and causes decrement in lung
                                           of New Hampshire’s having missed the                    guidance. Comments on EPA’s proposed                   function, aggravation of asthma, chest
                                           April 4, 2015 submission deadline.                      rulemaking were due on or before                       tightness, and respiratory and


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                                           25924               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           cardiovascular morbidity. The                           approach employed by New Hampshire                     compliance are sufficiently specific and
                                           commenter stated that such short-term                   to develop the emission limitations for                non-subjective such that two
                                           exposure is especially risky for children               Merrimack Station and included in the                  independent entities applying the
                                           with asthma. To support these                           State’s SIP submittal is consistent with               procedures would obtain the same
                                           statements regarding health effects, the                recommendations discussed in EPA’s                     result), and accountable (source specific
                                           commenter cited several EPA                             April 2014 guidance and adequately                     limitations must be permanent and must
                                           documents related to the final SO2                      protects against violation of the 1-hour               reflect the assumptions used in the SIP
                                           NAAQS and air quality trends. The                       SO2 NAAQS. EPA’s rationale for this                    demonstrations).
                                           commenter stated that EPA changed the                   conclusion is explained in further detail                 In our April 2014 guidance, EPA
                                           NAAQS from 140 ppb averaged over 24                     below.                                                 notes that past Agency guidance has
                                           hours to 75 ppb averaged over one hour                     The health effects information                      recommended that averaging times in
                                           in order to address these health impacts.               provided by the commenter is not in                    SO2 SIP emissions limitations should
                                           The commenter stated that as a result of                dispute in this rulemaking. This                       not exceed the averaging time of the
                                           the form of the standard, which is                      rulemaking instead addresses whether                   applicable NAAQS that the limit is
                                           evaluated through reference to the                      New Hampshire’s plan is adequate to                    intended to help attain (e.g., addressing
                                           fourth-highest daily maximum hourly-                    meet the previously established                        emissions averaged over one or three
                                           average concentrations in each year,                    NAAQS.                                                 hours). EPA’s April 2014 guidance also
                                           emission limits with an averaging                          As mentioned above, CAA section                     discusses the possibility of utilizing
                                           period longer than one hour are highly                  172(c) directs states with areas                       emission limitations with longer
                                           unlikely to be able to protect the 1-hour               designated as nonattainment to                         averaging times of up to 30 days, so long
                                           NAAQS. The commenter indicated that                     demonstrate that the submitted                         as the state meets various suggested
                                           the form of the NAAQS means that                        nonattainment plan provides for                        criteria to show that the longer-term
                                           ambient air quality can be evaluated as                 attainment of the NAAQS. EPA’s rules                   limits are comparably stringent to the 1-
                                           unsafe with as few as four hours of                     at 40 CFR part 51, subpart G further                   hour critical emission value that is
                                           elevated emissions over the course of a                 delineate the control strategy                         needed to meet the NAAQS. See EPA’s
                                           year. The commenter stated that even if                 requirements that SIPs must meet, and                  April 2014 guidance, pp. 22 to 39. The
                                           the 7-day limit is complied with,                       EPA has long required that all control                 guidance recommends that—should
                                           possible short-term emission ‘‘spikes’’                 strategies in nonattainment plans reflect              states elect to use longer averaging
                                           that may coincide with startup,                         four fundamental principles of                         times—the longer-term average limit
                                           shutdown, or control system                             quantification, enforceability,                        should be set at an adjusted level to
                                           malfunction events, for example, could                  replicability, and accountability. See                 reflect a stringency comparable to the 1-
                                           nevertheless cause ambient 1-hour SO2                   ‘‘State Implementation Plans; General                  hour average critical emission value
                                                                                                   Preamble for the Implementation of                     shown to provide for attainment
                                           concentrations sufficient to violate the
                                                                                                   Title I of the Clean Air Act Amendments                through a modeling analysis that the
                                           NAAQS. In support of this point, the
                                                                                                   of 1990; Proposed Rule,’’ 57 FR 13498                  plan otherwise would have set as an
                                           commenter provided language making
                                                                                                   (April 16, 1992) (General Preamble), at                emission limit.
                                           similar points excerpted from two EPA
                                                                                                   13567–68. Additional guidance is                          At the outset, EPA notes that the
                                           letters that had been included in the
                                                                                                   provided in EPA’s April 2014 guidance.                 specific examples of earlier EPA
                                           attachments to the commenter’s July 15,
                                                                                                   For SO2, there are generally two                       statements cited by the commenter (i.e.,
                                           2016 comments to New Hampshire,
                                                                                                   components needed to support an                        those contained in Exhibits 1, 2, 3, and
                                           specifically an August 12, 2010
                                                                                                   attainment demonstration submitted                     4 to Appendix A of the comment
                                           comment letter from EPA Region 7 to
                                                                                                   under section 172(c): (1) Emission                     submission) all pre-date the release of
                                           Kansas regarding the Sunflower                          limitations and other control measures                 EPA’s April 2014 guidance. As such
                                           Holcomb Station Expansion Project, and                  that assure implementation of                          these examples only reflect the Agency’s
                                           a February 1, 2012 comment letter from                  permanent, enforceable, and necessary                  development of its policy for
                                           EPA Region 5 to Michigan regarding a                    emission controls; and (2) a modeling                  implementing the 2010 SO2 NAAQS as
                                           draft construction permit for the Detroit               analysis that meets the requirements of                of the dates of their own issuance. At
                                           Edison Monroe Power Plant. The                          40 CFR part 51, appendix W and                         the time of their issuance, EPA had not
                                           commenter concluded that the 7-day                      demonstrates that these emission                       yet addressed the specific question of
                                           limit proposed for inclusion in the                     limitations and control measures                       whether it might be possible to devise
                                           State’s SIP has an averaging period that                provide for timely attainment of the                   an emission limit with an averaging
                                           is 168 times longer than that of the 1-                 primary SO2 NAAQS as expeditiously                     period longer than 1-hour, with
                                           hour NAAQS and should be revised to                     as practicable, but by no later than the               appropriate adjustments that would
                                           adequately protect the NAAQS. The                       applicable attainment date for the                     make it comparably stringent to an
                                           commenter added that hourly emissions                   affected area. In all cases, the emission              emission limit shown to attain 1-hour
                                           limits are not unreasonable, and cited                  limitations and control measures must                  emission level, that could adequately
                                           several examples of permits that impose                 be accompanied by appropriate methods                  ensure attainment of the SO2 NAAQS.
                                           such limits. Therefore, the commenter                   and conditions to determine compliance                 None of the pre-2014 EPA documents
                                           concluded that a 1-hour emissions limit                 with the respective emission limitations               cited by the commenter address this
                                           should be imposed.                                      and control measures. Furthermore, in                  question; consequently, it is not
                                              Response 1: EPA appreciates the                      all cases, the emission limitations and                reasonable to read any of them as
                                           commenter’s concerns about the                          control measures must be: Quantifiable                 rejecting that possibility. However,
                                           appropriateness of approving                            (i.e., a specific amount of emission                   EPA’s April 2014 guidance specifically
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                                           nonattainment plans with emission                       reduction can be ascribed to the                       addressed this issue as it pertains to
                                           limitations that apply over a longer time               measures), fully enforceable (specifying               requirements for SIPs for SO2
                                           period than the 1-hour form of the 2010                 clear, unambiguous, and measurable                     nonattainment areas under the 2010
                                           SO2 NAAQS. We discussed similar                         requirements for which compliance can                  NAAQS, especially with regard to the
                                           issues in EPA’s April 2014 guidance. In                 be practicably determined), replicable                 use of appropriately set comparably
                                           this case, EPA has concluded that the                   (the procedures for determining                        stringent limitations based on averaging


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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                           25925

                                           times as long as 30 days (see p. 2). EPA                   As specified in 40 CFR 50.17(b), the                   EPA recognizes that some sources
                                           developed this guidance pursuant to a                   1-hour primary SO2 NAAQS is met at an                  may have highly variable emissions, for
                                           lengthy stakeholder outreach process                    ambient air quality monitoring site                    example due to variations in fuel sulfur
                                           regarding implementation strategies for                 when the 3-year average of the annual                  content and operating rate, that can
                                           the 2010 NAAQS, which had not yet                       99th percentile of daily maximum 1-                    make it extremely difficult, even with a
                                           concluded (or in some cases even                        hour concentrations is less than or equal              well-designed control strategy, to ensure
                                           begun) when the documents cited by the                  to 75 ppb. In a year with 365 days of                  in practice that emissions for any given
                                           commenter were issued. As such, EPA’s                   valid monitoring data, the 99th                        hour do not exceed the critical emission
                                           April 2014 guidance was the first                       percentile would be the fourth highest                 value. EPA also acknowledges the
                                           instance in which the Agency provided                   daily maximum 1-hour value. The 2010                   concern that longer-term emission limits
                                           recommended guidance for that                           SO2 NAAQS, including this form of                      can allow short periods with emissions
                                           component of this action. Consequently,                 determining compliance with the                        above the critical emission value,
                                           EPA does not view those prior EPA                       standard, was upheld by the U.S. Court                 which, if coincident with
                                           statements as conflicting with the                      of Appeals for the District of Columbia                meteorological conditions conducive to
                                           Agency’s guidance addressing this                       Circuit in Nat’l Envt’l Dev. Ass’n’s Clean             high SO2 concentrations, could create
                                           specific question of how to devise a                    Air Project v. EPA, 686 F.3d 803 (D.C.                 the possibility of a NAAQS exceedance
                                           longer-term limit that is comparably                    Cir. 2012). Because the standard has this              occurring on a day when an exceedance
                                           stringent to a 1-hour critical emission                 form, a single exceedance of the                       would not have occurred if emissions
                                           value that has been modeled to attain                   numerical limit of 75 ppb does not                     were continuously controlled at the
                                           the NAAQS. Moreover, EPA notes that                     constitute a violation of the standard.                level corresponding to the 1-hour
                                           the commenter has not raised specific                   Instead, at issue is whether a source                  critical emission value. However, for
                                           objections to the general policy and                    operating in compliance with a properly                several reasons, EPA finds that the
                                           technical rationale EPA provided in its                 set longer-term average could cause                    approach recommended in its April
                                           proposed approval or in EPA’s April                     exceedances, and if so the resulting                   2014 guidance document suitably
                                           2014 guidance for why such longer-term                  frequency and magnitude of such                        addresses this concern, and that in this
                                           averaging-based limits may in specific                  exceedances. In particular, what matters               case, New Hampshire has devised a
                                           cases be adequate to ensure NAAQS                       is whether EPA can have reasonable                     longer-term limit that is comparably
                                           attainment, which we again summarize                    confidence that a properly set longer-                 stringent to the 1-hour critical emission
                                           below.                                                  term average limit will provide that the               value that suitably provides for meeting
                                              EPA’s April 2014 guidance provides                   3-year average of annual fourth highest                the NAAQS.
                                           an extensive discussion of EPA’s                        daily maximum values will be at or
                                           rationale for positing that an                                                                                    First, from a practical perspective,
                                                                                                   below 75 ppb. A synopsis of EPA’s
                                           appropriately-set, comparably stringent                                                                        EPA expects the actual emission profile
                                                                                                   review of how to judge whether such
                                           limitation based on an averaging time as                                                                       of a source subject to an appropriately
                                                                                                   plans ‘‘provide for attainment,’’ based
                                           long as 30 days can, based on a                                                                                set longer-term average limit to be
                                                                                                   on modeling of projected allowable
                                           situation’s specific facts, be found to                                                                        similar to the emission profile of a
                                                                                                   emissions and in light of the form for
                                           provide for attainment of the 2010                                                                             source subject to an analogous 1-hour
                                                                                                   determining attainment of the NAAQS
                                           primary SO2 NAAQS, provided it is                                                                              average limit. EPA expects this
                                                                                                   at monitoring sites, follows.
                                           shown to be comparably stringent to a                                                                          similarity because it has recommended
                                                                                                      For SO2 nonattainment plans based                   that the longer-term average limit be set
                                           1-hour critical emission value that is
                                                                                                   on 1-hour emission limits, the standard                at a level that is comparably stringent to
                                           demonstrated through modeling to
                                                                                                   approach is to conduct modeling using                  the otherwise applicable 1-hour limit
                                           attain the NAAQS. Essentially, to
                                                                                                   fixed emission rates. The maximum                      (reflecting a downward adjustment from
                                           achieve such comparable stringency,
                                                                                                   emission rate that would be modeled to                 the critical emission value) and that
                                           rather than simply convert an attaining
                                                                                                   result in attainment (i.e., in an ‘‘average            takes the source’s emissions profile into
                                           1-hour emission rate to a longer term
                                                                                                   year’’ 1 shows fewer than four days with               account. As a general matter, EPA
                                           limit at the same level, it is expected
                                                                                                   maximum hourly levels exceeding 75                     would expect that any emission limit
                                           that an adjustment would be needed to
                                                                                                   ppb) is labeled the ‘‘critical emission                with an averaging time longer than 1
                                           lower the emission rate as the averaging
                                                                                                   value.’’ The modeling process for                      hour would need to reflect a downward
                                           time is increased. It is first necessary to
                                                                                                   identifying this critical emission value               adjustment to compensate for the loss of
                                           identify a modeled 1-hour emission
                                                                                                   inherently considers the numerous                      stringency inherent in applying a longer
                                           value that attains the NAAQS before
                                                                                                   variables that affect ambient                          term average limit. This expectation is
                                           deriving a comparably stringent longer-
                                                                                                   concentrations of SO2, such as                         based on the idea that a limit based on
                                           term emission limit, i.e., an emission
                                                                                                   meteorological data, background                        the 30-day average of emissions, for
                                           limit that has been appropriately
                                                                                                   concentrations, and terrain. In the                    example, at a particular level is likely to
                                           adjusted downward. In evaluating this
                                                                                                   standard approach, the state would then                be a less stringent limit than a 1-hour
                                           option, EPA considered in the April
                                                                                                   provide for attainment by setting a                    limit at the same level, since the control
                                           2014 guidance the nature of the
                                                                                                   continuously applicable 1-hour                         level needed to meet a 1-hour limit
                                           standard, conducted detailed analyses
                                                                                                   emission limitation at this critical                   every hour is likely to be greater than
                                           of the impact of the use of 30-day
                                                                                                   emission value.                                        the control level needed to achieve the
                                           average limits on the prospects for
                                           attaining the standard, and carefully                                                                          same limit on a 30-day average basis.
                                                                                                     1 An ‘‘average year’’ is used to mean a year with
                                           reviewed how best to achieve an                                                                                EPA’s approach for downward
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                                                                                                   average air quality. While 40 CFR part 50, appendix
                                           appropriate balance among the various                   T provides for averaging three years of 99th           adjustment is to account for the
                                           factors that warrant consideration in                   percentile daily maximum values (e.g., the fourth      expected variability in emissions over
                                           judging whether a state’s nonattainment                 highest maximum daily concentration in a year          the time period up to 30 days to achieve
                                                                                                   with 365 days with valid data), this discussion and
                                           plan provides for attainment. Id. at pp.                an example used later in EPA’s response to
                                                                                                                                                          comparable stringency to the emissions
                                           22 to 39. See also id. at appendices B,                 Comment 1 uses a single ‘‘average year’’ in order      and expected air quality impacts for a 1-
                                           C, and D.                                               to simplify the illustration of relevant principles.   hour period. As a result, EPA expects


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                                           25926               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           either form of emission limit to yield                  In this simplified example, assume a                   plan in the present that will guarantee
                                           comparable air quality.                                 zero background concentration, which                   that attainment will occur in the future.
                                              Second, from a more theoretical                      allows one to assume a linear                          A variety of factors can cause a well-
                                           perspective, EPA has compared the                       relationship between emissions and air                 designed nonattainment plan to fail and
                                           likely air quality with a source having                 quality. (A nonzero background                         unexpectedly not result in attainment,
                                           maximum allowable emissions under an                    concentration would make the                           for example if meteorology occurs that
                                           appropriately set longer-term limit, as                 mathematics more difficult but would                   is more conducive to poor air quality
                                           compared to the likely air quality with                 give similar results.) Air quality will                than was anticipated in the plan.
                                           the source having maximum allowable                     depend on how much emissions occur                     Therefore, in determining whether a
                                           emissions under the comparable 1-hour                   on which critical hours, but suppose                   plan meets the requirement to provide
                                           limit. In this comparison, in the 1-hour                that emissions at the relevant times on                for attainment, EPA’s task is commonly
                                           average limit scenario, the source is                   these five days are 800 pounds per hour,               to judge not whether the plan provides
                                           presumed at all times to emit at the                    1,100 pounds per hour, 500 pounds per                  absolute certainty that attainment will
                                           critical emission value, and in the                     hour, 900 pounds per hour, and 1,200                   in fact occur, but rather whether the
                                           longer-term average limit scenario, the                 pounds per hour, respectively. (This is                plan provides an adequate level of
                                           source is presumed occasionally to emit                 a conservative example because the                     confidence of prospective NAAQS
                                           more than the critical emission value                   average of these emissions, 900 pounds                 attainment. From this perspective, in
                                           but on average, and presumably at most                  per hour, is well over the 30-day average              evaluating use of a longer-term limit up
                                           times, to emit well below the critical                  emission limit of 700 pounds per hour.)                to 30-days, EPA must weigh the likely
                                           emission value. In an ‘‘average year,’’                 These emissions would result in daily                  net effect on air quality. Such an
                                           compliance with the 1-hour limit is                     maximum 1-hour concentrations of 80                    evaluation must consider the risk that
                                           expected to result in three exceedance                  ppb, 99 ppb, 40 ppb, 67.5 ppb, and 84                  occasions with meteorology conducive
                                           days (i.e., three days with maximum                     ppb. In this example, the fifth day                    to high concentrations will have
                                           hourly values above 75 ppb) and a                       would have an exceedance that would                    elevated emissions leading to
                                           fourth day with a maximum hourly                        not otherwise have occurred, but the                   exceedances that would not otherwise
                                           value at 75 ppb. By comparison, with                    third and fourth days would not have                   have occurred, and must also weigh the
                                           the source complying with a longer-term                 exceedances that otherwise would have                  likelihood that the requirement for
                                           limit, it is possible that additional                   occurred. In this example, the fourth                  lower emissions on average will result
                                           exceedances would occur that would                      highest maximum daily concentration                    in days not having exceedances that
                                           not occur in the 1-hour limit scenario (if              under the 30-day average would be 67.5                 would have been expected with
                                           emissions exceed the critical emission                  ppb.                                                   emissions at the critical emission value.
                                           value at times when meteorology is                         This simplified example illustrates                 Additional policy considerations, such
                                           conducive to poor air quality). However,                the findings of a more complicated                     as in this case the desirability of
                                           this comparison must also factor in the                 statistical analysis that EPA conducted                accommodating real world emissions
                                           likelihood that exceedances that would                  using a range of scenarios using actual                variability without significant risk of
                                           be expected in the 1-hour limit scenario                plant data. As described in appendix B                 violations, are also appropriate factors
                                           would not occur in the longer-term limit                of EPA’s April 2014 guidance, EPA                      for EPA to weigh in judging whether a
                                           scenario. This result arises because the                found that the requirement for lower                   plan provides a reasonable degree of
                                           longer-term limit requires lower                        average emissions is highly likely to                  confidence that the plan will lead to
                                           emissions most of the time (because the                 yield better air quality than is required
                                                                                                                                                          attainment. Based on these
                                           limit is set below the critical emission                with a comparably stringent 1-hour
                                                                                                                                                          considerations, especially given the
                                           value), so a source complying with an                   limit. Based on analyses described in
                                                                                                                                                          high likelihood that a continuously
                                           appropriately set longer-term limit is                  appendix B, EPA expects that an
                                                                                                                                                          enforceable limit, averaged over as long
                                           likely to have lower emissions at critical              emission profile with maximum
                                                                                                                                                          as 30 days, determined in accordance
                                           times than would be the case if the                     allowable emissions under an
                                                                                                                                                          with EPA’s April 2014 guidance, will
                                           source were emitting as allowed with a                  appropriately set comparably stringent
                                                                                                                                                          result in attainment, EPA posits as a
                                           1-hour limit.                                           30-day average limit is likely to have the
                                              As a hypothetical example to                                                                                general matter that such limits, if
                                                                                                   net effect of having a lower number of
                                           illustrate these points, suppose a source                                                                      appropriately determined, can
                                                                                                   exceedances and better air quality than
                                           that always emits 1,000 pounds of SO2                   an emission profile with maximum                       reasonably be considered to provide for
                                           per hour, which results in air quality                  allowable emissions under a 1-hour                     attainment of the 2010 SO2 NAAQS.
                                           exactly at the level of the NAAQS (i.e.,                emission limit at the critical emission                Furthermore, as discussed below, EPA
                                           results in a design value of 75 ppb).                   value. This result provides a compelling               concludes that in this case, New
                                           Suppose further that in an ‘‘average                    rationale for allowing the use of a longer             Hampshire has demonstrated that its
                                           year,’’ these emissions cause the five                  averaging period, in appropriate                       longer-term limit was appropriately
                                           highest maximum daily average 1-hour                    circumstances where the facts indicate                 determined and provides for NAAQS
                                           concentrations to be 100 ppb, 90 ppb, 80                that this result can be expected to occur.             attainment.
                                           ppb, 75 ppb, and 70 ppb. Then suppose                      The question then becomes whether                      As stated by the commenter, the limit
                                           that the source becomes subject to a 30-                this approach—which is likely to                       included in the State’s SIP submittal is
                                           day average emission limit of 700                       produce a lower number of overall                      for a period of 7 days, or 168 hours. As
                                           pounds per hour, i.e., at a level adjusted              exceedances even though it may                         stated above, EPA posits that limits
                                           downward from 1,000 pounds per hour                     produce some unexpected exceedances                    based on periods of as long as 30 days
                                           by 30%. It is theoretically possible for                above the 1-hour critical emission                     (720 hours), determined in accordance
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                                           a source meeting this limit to have                     value—meets the requirement in                         with our April 2014 guidance, can, in
                                           emissions that occasionally exceed                      sections 110(a) and 172(c) for state                   many cases, be reasonably considered to
                                           1,000 pounds per hour, but with a                       implementation plans to ‘‘provide for                  provide for attainment of the 2010 SO2
                                           typical emissions profile emissions                     attainment’’ of the NAAQS. For SO2, as                 NAAQS. In EPA’s April 2014 guidance,
                                           would much more commonly be                             for other pollutants, it is generally                  EPA supplied an analysis of the impact
                                           between 600 and 800 pounds per hour.                    impossible to design a nonattainment                   of emissions variability on air quality


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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                                 25927

                                           and explained that it may be possible in                part 51, appendix W).3 In 2005, EPA                    New Hampshire could reasonably have
                                           some specific cases to develop control                  promulgated AERMOD as the Agency’s                     chosen to establish 1-hour limits does
                                           strategies that account for variability in              preferred near-field dispersion modeling               not mean that EPA should disapprove
                                           1-hour emissions rates through                          for a wide range of regulatory                         limits with comparable stringency using
                                           emissions limits with averaging times as                applications addressing stationary                     longer averaging times. In this instance,
                                           long as 30 days and still provide for                   sources (for example in estimating SO2                 the State’s emission limit for Merrimack
                                           attainment of the 2010 SO2 NAAQS.                       concentrations) in all types of terrain                Station utilizes a 7-day average, and
                                           Since seven days (168 hours) are well                   based on extensive developmental and                   New Hampshire has shown it to be
                                           within the period of 30 days (720                       performance evaluation. Supplemental                   comparably stringent to a 1-hour limit at
                                           hours), EPA has concluded that a limit                  guidance on modeling for purposes of                   the critical emission level, which the
                                           for Merrimack Station based on a period                 demonstrating attainment of the SO2                    State demonstrated to suitably provide
                                           of 7 days and determined in accordance                  standard is provided in appendix A to                  for attainment of the NAAQS.
                                           with EPA’s April 2014 guidance can be                   EPA’s April 2014 guidance. Appendix A                     Based on EPA’s review of the State’s
                                           reasonably considered to provide for                    provides extensive guidance on the                     submittal, EPA finds that the 7-day
                                           attainment.                                             modeling domain, the source inputs,                    average limit of 0.39 pounds (lb) per
                                              EPA’s April 2014 guidance offers                     assorted types of meteorological data,                 million British thermal units (MMBtu)
                                           specific recommendations for                            and background concentrations.                         established for Merrimack Station
                                           determining an appropriate longer-term                  Consistency with the recommendations                   provides for a suitable alternative to
                                           average limit. The recommended                          in this guidance is generally necessary                establishing a 1-hour average emission
                                           method starts with determination of the                 for the attainment demonstration to                    limit for this source. New Hampshire
                                           1-hour emission limit that would                        offer adequately reliable assurance that               used a suitable data profile in an
                                           provide for attainment (i.e., the 1-hour                the plan provides for attainment.                      appropriate manner and has thereby
                                           critical emission value), and applies an                   As stated previously, attainment                    applied an appropriate adjustment,
                                           adjustment factor to determine the                      demonstrations for the 2010 1-hour                     yielding emission limits that have
                                           (lower) level of the longer term average                primary SO2 NAAQS must demonstrate                     comparable stringency to the 1-hour
                                           emission limit that would be estimated                  future attainment and maintenance of                   average limit that the State determined
                                           to have a stringency comparable to the                  the NAAQS in the entire area                           would otherwise have been necessary to
                                           otherwise necessary 1-hour emission                     designated as nonattainment (i.e., not                 provide for attainment. While the
                                           limit. This method uses a database of                   just at the violating monitor) by using                longer-term averaging limit allows
                                           continuous emission data reflecting the                 air quality dispersion modeling (see                   occasions in which emissions may be
                                           type of control that the source will be                 appendix W to 40 CFR part 51) to show                  higher than the level that would be
                                           using to comply with the SIP emission                   that the mix of sources and enforceable                allowed with the 1-hour limit, the
                                           limits, which (if compliance requires                   control measures and emission rates in                 State’s limits compensate by requiring
                                           new controls) may require use of a                      an identified area will not lead to a                  average emissions to be adequately
                                           different emission database, e.g., from a               violation of the SO2 NAAQS. For a                      lower than the level that would
                                           different but comparable facility using                 short-term (i.e., 1-hour) standard, EPA                otherwise have been required by a 1-
                                           similar emissions control equipment.                    asserts that dispersion modeling, using                hour average limit. The September 28,
                                           The recommended method involves                         allowable emissions and addressing                     2017 notice of proposed rulemaking
                                           using these data to compute a complete                  stationary sources in the affected area                provided a detailed description of EPA’s
                                           set of emission averages, computed                      (and in some cases those sources located               rationale for the proposed finding that
                                           according to the averaging time and                     outside the nonattainment area which                   the 7-day average limit for Merrimack
                                           averaging procedures of the prospective                 may affect attainment in the area) is                  Station is adequate to provide for
                                           emission limitation. In this                            technically appropriate, efficient, and                attainment, and the commenter has not
                                           recommended method, the ratio of the                    effective in demonstrating attainment in               raised any concerns about this approach
                                           99th percentile among these longer-term                 nonattainment areas because it takes                   that we have not already addressed.
                                                                                                   into consideration combinations of                        Comment 2: The commenter states
                                           averages to the 99th percentile of the 1-
                                                                                                   meteorological and emission source                     that the 7-day average approach would
                                           hour values represents an adjustment
                                                                                                   operating conditions that may                          mask significant hours in which
                                           factor that may be multiplied by the
                                                                                                   contribute to peak ground-level                        emissions are above safe levels. The
                                           candidate 1-hour emission limit (i.e.,
                                                                                                   concentrations of SO2.                                 commenter then presents information
                                           the critical emission value) to determine
                                                                                                      Regarding the commenter’s position                  regarding historic hourly emissions
                                           a longer-term average emission limit
                                                                                                   that only hourly SO2 emissions limits                  from Merrimack Station after the flue
                                           that may be considered comparably
                                                                                                   are reasonable, citing the examples                    gas desulfurization (FGD) scrubber
                                           stringent.2 The guidance also addresses
                                                                                                   supplied in the commenter’s                            system was installed. Specifically, using
                                           a variety of related topics, such as the
                                                                                                   submission, EPA agrees that 1-hour                     data from EPA’s Air Markets Program
                                           potential utility of setting supplemental
                                                                                                   limits can be reasonable and protective                Data (AMPD), the commenter identified
                                           emission limits, such as mass-based
                                                                                                   so long as they are adequately supported               over 224 individual hours on 62
                                           limits, to reduce the likelihood and/or
                                                                                                   by an attainment demonstration                         separate days in the period between
                                           magnitude of elevated emission levels
                                                                                                   establishing those limits as meeting the               January 1, 2012, through September 30,
                                           that might occur under the longer-term
                                                                                                   NAAQS. In this action, EPA is not                      2017, during which emissions were
                                           emission rate limit.
                                                                                                   changing its position regarding the                    above the 1-hour critical emission rate
                                              Preferred air quality models for use in
                                                                                                   sufficiency in meeting the NAAQS with                  of 0.54 lb/MMBtu,4 i.e., the maximum
                                           regulatory applications are described in
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                                           appendix A of the Guideline (40 CFR                     1-hour emissions limitations to which
                                                                                                                                                            4 In multiple instances, the Commenter appears to
                                                                                                   other facilities, as cited by the
                                                                                                                                                          inaccurately assume the critical emission rate is
                                             2 For example, if the critical emission value is      commenter, are subject. The fact that                  0.53 lb/MMBtu. The mass-based critical emission
                                           1,000 pounds of SO2 per hour, and a suitable                                                                   value, as calculated by the State’s modeling, is
                                           adjustment factor is determined to be 0.70 (i.e.,         3 The most recent version of the Guideline was       2,544 lb/hour, which is equivalent to the critical
                                           70%), the recommended longer term average limit         published on January 17, 2017 (see 82 FR 5182) and     emission rate of 0.54 lb/MMBtu at the maximum
                                           would be 700 pounds per hour.                           became effective on May 22, 2017.                                                                Continued




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                                           25928                Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           hourly emission rate determined to be                   violated the current 7-day emission                       (2) Merrimack Station is subject to
                                           protective of the NAAQS. The                            limit, had it been in place at the time,               emission monitoring and reporting
                                           commenter indicated that during the                     and therefore these data are not                       requirements under the Acid Rain
                                           same period, there do not appear to                     evidence that compliance with the 7-                   Program (40 CFR part 75). Under the
                                           have been any 7-day periods in which                    day limit would result in a higher risk                Acid Rain Program, Merrimack Station
                                           average emissions exceeded the 0.39 lb/                 of NAAQS violations. Each of these                     must hold sufficient emission
                                           MMBtu limit in the SIP revision. The                    points is discussed in greater detail                  allowances to account for its SO2
                                           commenter asserts that this disparity,                  below.                                                 emissions. For hours in which direct,
                                           i.e., the fact that emissions during over                  By reviewing the AMPD emissions                     quality-assured measurements from the
                                           224 hours on 62 separate days exceeded                  data using EPA’s Field Audit Checklist                 continuous monitoring systems (CEMS)
                                           the 1-hour critical emission rate of 0.54               Tool (FACT) 5 for the period between                   are not available, EPA’s Acid Rain
                                           lb/MMBtu while the 7-day limit was not                  January 1, 2012, and March 31, 2018,                   Program regulations require that high
                                           exceeded during the time period from                    EPA found 227 hours with emissions                     emission values are calculated or
                                           January 2012 through September 2017,                    above 0.54 lb/MMBtu, a number that is                  substituted for the emissions that are
                                           indicates that the downwardly adjusted                  consistent with the ‘‘over 224 hours’’                 not monitored in order to ensure that
                                           0.39 lb/MMBtu 7-day limit is                            identified by the commenter. In the                    the source holds sufficient allowances
                                           inadequate to protect the NAAQS.                        following discussion, EPA identifies the               to account conservatively for its
                                              Response 2: The commenter implies                    number of hours of those 227 hours that                emissions. See 40 CFR part 75 subpart
                                           that occasions of emissions above the 1-                are not appropriate to use in the                      D. As described in New Hampshire’s
                                           hour critical emission rate,                            analysis of the adequacy of the 7-day                  response to comments for its
                                           notwithstanding compliance with a 7-                    emission limit. EPA has included a                     nonattainment area plan, the CEMS at
                                           day limit, create an unacceptable risk of               spreadsheet in the docket of this action               Merrimack Station was certified on
                                           additional exceedances that would                       which contains the relevant data used in               November 21, 2011 using only the low
                                           result in violation of the standard. EPA                EPA’s analysis.                                        range of a dual range analyzer to
                                           does not agree with this notion, and the
                                                                                                      (1) The FGD at Merrimack Station first              measure from 0 to 300 parts per million
                                           commenter has not supplied evidence to
                                                                                                   became operational on September 28,                    (ppm) SO2 of in-stack exhaust gas.
                                           support it. Furthermore, in making this
                                                                                                   2011. Under the conditions established                 When the low range was exceeded, i.e.,
                                           claim, the commenter is relying on an
                                                                                                   in the State’s permit TP–0008,                         in-stack exhaust gas exceeded 300 ppm
                                           emissions dataset that, for the reasons
                                           enumerated below, is not appropriate                    Merrimack Station was not permitted to                 SO2, a calculated value of 200% of the
                                           for assessing the prospective likelihood                operate MK2, one of its two utility                    maximum potential or uncontrolled
                                           of Merrimack Station emitting more                      boilers, unless the FGD was in                         concentration was reported to ensure
                                           than the critical emission value, which                 operation. Merrimack Station’s other                   that under reporting did not occur for
                                           may result in unsafe air quality. First,                utility boiler, MK1, was permitted to                  purposes of the Acid Rain Program. As
                                           the dataset includes emissions from                     bypass the FGD system for no more than                 part of a periodic reassessment of the
                                           periods during which Merrimack                          840 hours per consecutive 12-month                     appropriate analyzer ranges, Merrimack
                                           Station was not subject to State permit                 period. Both of these permit conditions                Station retained a low range
                                           conditions on the operation of its FGD                  became applicable and enforceable as of                configuration and adjusted it to measure
                                           scrubber system, and is therefore not                   July 1, 2013. (This emission bypass                    from 0 to 150 ppm on January 28, 2013.
                                           representative of current and expected                  provision is no longer permitted under                 See section 2.1.1.5 of appendix A to 40
                                           future emissions. Second, the dataset                   the September 1, 2016 TP–0189 permit.)                 CFR part 75. On February 4, 2015,
                                           includes some emission values that are                  Prior to July 1, 2013, the facility was not            Merrimack Station began calibrating and
                                           unrealistically high because they are                   subject to enforceable permit conditions               quality-assuring the high range of the
                                           calculated or substitute data used for                  requiring operation of the FGD. During                 dual range analyzer from 150 to 2,600
                                           purposes of determining compliance                      2012, Merrimack Station bypassed the                   ppm, while the lower range continued
                                           with EPA’s Acid Rain Program rather                     FGD for emissions from MK1 on several                  to be quality assured to measure
                                           than measured data used for                             occasions, the last of which occurred on               between 0 and 150 ppm. In accordance
                                           determining emissions for compliance                    November 7, 2012. As such, EPA does                    with Acid Rain Program requirements,
                                           with the 7-day limit. Third, emission                   not view emissions occurring at                        Merrimack Station was required to
                                           data for Merrimack Station show that                    Merrimack Station prior to July 1, 2013                report calculated emissions at 200% of
                                           the facility has rarely emitted above the               as being representative of current or                  the maximum potential or uncontrolled
                                           critical emission rate of 0.54 lb/MMBtu                 expected future emissions because prior                concentration during the period from
                                           since September 1, 2016, when the                       to this date the relevant, enforceable                 November 21, 2013 to February 4, 2015
                                           State’s permit TP–0189 became                           permit provisions that required                        when concentrations exceeded the
                                           applicable and enforceable. Fourth, the                 operation of the emission control system               lower range, i.e., in-stack exhaust gas
                                           State’s rate-based emission limit is                    at Merrimack Station, as contained in                  exceeded 300 ppm. See section 2.1.1.4(f)
                                           designed to ensure consistent control at                permit number TP–0008, were not                        of Appendix A to 40 CFR part 75. These
                                           all load levels during operation, so an                 effective. Of the 227 hours with                       hours are marked as SO2 Method Of
                                           exceedance of the critical emission rate                emissions above 0.54 lb/MMBtu, there                   Determination Code (MODC) 19 in the
                                           (in lb/MMBtu) does not necessarily                      were 188 hours that occurred prior to                  FACT database and were reported as
                                           mean that emissions are higher than the                 July 1, 2013, leaving 39 hours for further             such in the hourly electronic emissions
                                           critical emission value (in lb/hour).                   analysis.                                              records. Additional CEMS outage hours
                                                                                                                                                          that used substitute data calculated as
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                                           Fifth and finally, if actual measured
                                           emissions from Merrimack Station had                      5 Field Audit Checklist Tool (FACT) version          the average of the hour before and after,
                                           occurred at the levels indicated by the                 1.2.0.1, available for download at: www.epa.gov/       reported as SO2 MODC 06, are not
                                                                                                   airmarkets/field-audit-checklist-tool-fact. FACT       measured emissions data but rather are
                                           commenter, the facility would have                      provides users with metadata, including ‘‘method of
                                                                                                   determination codes’’ (MODC), beyond the
                                                                                                                                                          substitute data hours. EPA concludes
                                           rated capacity of Merrimack’s two coal-fired electric   information available using the AMPD website           from the CEMS data that data points
                                           generating units, MK1 and MK2.                          referenced by the Commenter.                           flagged as calculated or substitute data


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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                          25929

                                           with SO2 MODC 06 or 19 are not                             Only one hour had emissions above                   periods, 26 occurred in 2012, while the
                                           appropriate for use in assessing NAAQS                  the critical emission value of 2,544 lb/               facility was still permitted to bypass the
                                           compliance in this case because these                   hour. Specifically, Merrimack emitted                  FGD system, a practice that is not
                                           values do not represent actual measured                 2,578.6 pounds of SO2 on December 1,                   permitted under the conditions of the
                                           emissions during those hours.                           2015 during the 7 a.m. hour.                           September 2016 permit TP–0189. Even
                                              Data points flagged as SO2 MODC 06                      EPA does not regard the single hour                 by omitting data points flagged as
                                           or 19 account for 32 hours of the                       on December 1, 2015 at 7 a.m., during                  calculated or substitute data, none of the
                                           remaining 39 emissions data points over                 which Merrimack Station had emissions                  7-day emission averages associated with
                                           0.54 lb/MMBtu, leaving seven hours for                  over the critical emission value, by itself            these 26 7-day periods in 2012 would
                                           further analysis.                                       as representing a serious risk for causing             have met the 7-day emission limit, had
                                              (3) The emission profile for                         a violation of the NAAQS. EPA has                      it been in place at the time.
                                           Merrimack Station, since the issuance of                previously acknowledged that there                        The one remaining 7-day period
                                           the September 2016 permit containing                    could possibly be hourly emission                      ended on December 11, 2014, and the
                                           the 7-day average SO2 emissions limit,                  levels above the critical emission value               associated 7-day emission average of
                                           shows that exceedances of the critical                  from a source complying with a longer-                 0.419 lb/MMBtu would have exceeded
                                           emission rate, i.e., 0.54 lb/MMBtu, are                 term average emission limit, e.g., a 7-                the emission limit of 0.39 lb/MMBtu, if
                                           infrequent. In the period from                          day limit. As stated in the proposal, an               data points flagged as calculated or
                                           September 1, 2016, when the State’s                     hour where emissions are above the                     substitute data were treated as actual
                                           permit TP–0189 became applicable and                    critical emission value does not                       emissions. By omitting the calculated or
                                           enforceable, to March 31, 2018,                         necessarily mean that a NAAQS                          substitute data from this time period,
                                           Merrimack Station has emitted at a level                exceedance is occurring in that hour.                  the 7-day emission average ending on
                                           higher than the 0.54 lb/MMBtu on three                  Similarly, an individual hour where                    December 11, 2014 would have been
                                           hours out of 3,109 operating hours with                 emissions are above the level of the                   0.20 lb/MMBtu, which would comply
                                           measured emissions data, or less than                   comparably stringent 7-day limit (0.39                 with the 7-day limit of 0.39 lb/MMBtu,
                                           0.1%. In addition to the SO2 emission                   lb/MMBtu in this instance) does not                    had it been in place at the time.
                                           limit, the September 1, 2016 permit TP–                 mean that an exceedance of the NAAQS                      This finding contradicts the
                                           0189 included a more stringent limit for                is occurring in that hour, especially if               commenter’s assertion that the ‘‘over
                                           the SO2 removal efficiency of the                       the level of emissions is below the                    224’’ individual hours with emissions
                                           scrubber than was included in the TP–                   critical emission value. This notion also              purportedly higher than the critical
                                           0008 permit. In addition, TP–0189                       does not take into account the possible                emission rate would not have resulted
                                           prohibits the use of the emergency stack                exceedances that would be expected                     in an exceedance of the 7-day average
                                           to bypass emissions controls except as                  with emissions always at the critical                  limit. On the contrary, even if the
                                           necessary to prevent severe damage to                   emission value that would otherwise be                 emissions with reported emissions
                                           equipment or potential injury to facility               avoided because emissions are generally                above the critical emission value did
                                           personnel. The infrequency of emissions                 required to be lower (in this case, on                 represent actual emissions, which EPA
                                           above 0.54 lb/MMBtu since September                     average 27% lower). Based on this                      argues in the previous sections is
                                           1, 2016 indicates that the multiple SO2                 reasoning, EPA concludes that the risk                 incorrect, Merrimack Station would
                                           emission control provisions contained                   of an exceedance for the one hour with                 have been out of compliance with the 7-
                                           in TP–0189, as described above, have                    emissions above the critical emission                  day limit permit had it been in effect at
                                           been successful in consistently reducing                value of 2,544 lb/hour during 4.75 years               the time.
                                           emissions from Merrimack Station.                       of emissions from Merrimack Station                       Therefore, based on the reasoning
                                           Based on this evidence, EPA expects                     (from July 1, 2013 to March 31, 2018)                  supplied in the sections above, EPA
                                           that future instances of emissions from                 does not suggest that a violation of the               disagrees with the commenter that
                                           Merrimack Station above 0.54 lb/                        NAAQS is likely to have occurred.                      emissions data from Merrimack Station
                                           MMBtu will continue to be extremely                        (5) Notwithstanding the explanations                demonstrate the inadequacy of the 7-day
                                           rare.                                                   above regarding the appropriateness of                 emission limit imposed by the State.
                                              (4) While emissions exceeded 0.54 lb/                omitting certain data points from                      Rather, the data most representative of
                                           MMBtu during each of the seven hours                    considering NAAQS compliance, such                     Merrimack Station’s current and
                                           since July 1, 2013 (of which only three                 emissions data, if they had actually been              expected future emissions indicate that
                                           hours exceeded 0.54 lb/MMBtu since                      representative of real emissions, would                the facility, when complying with the
                                           September 1, 2016, as described above),                 have caused a violation of the permit                  applicable permit restrictions, is
                                           for six of these hours the total mass-                  conditions for Merrimack Station, if the               extremely unlikely to cause a violation
                                           based emission rate, measured in lb/                    7-day permit limit had been in place at                of the SO2 NAAQS. The emissions data
                                           hour, did not exceed the critical                       the time. EPA has evaluated the                        presented by the commenter are not
                                           emission value of 2,544 lb/hour. Of                     Merrimack Station emissions data for                   representative of Merrimack Station’s
                                           those six hours, the highest emission                   the period January 1, 2012 through                     current and expected future emissions,
                                           level was 1,386.6 pounds of SO2, well                   March 31, 2017 in accordance with the                  and are therefore not appropriate for use
                                           below the critical emission value, and                  7-day average emission rate limit, both                in assessing NAAQS compliance in this
                                           the other emission values range from 1.1                with and without the omission of data                  case.
                                           to 843.5 pounds SO2. Based on the                       points flagged as calculated or substitute                EPA offers the following additional
                                           State’s attainment modeling                             data.                                                  discussion to further respond directly
                                           demonstration, these lower emission                        This evaluation found 27 periods                    regarding the sufficiency of an
                                           values would not be expected to result                  during which the associated 7-day                      appropriately-calculated, longer-term
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                                           in exceedances of the NAAQS. That is,                   emission average would have violated                   average limit, up to 30-days, with
                                           New Hampshire’s modeling indicates                      the terms of the permit conditions, had                comparable stringency to a 1-hour
                                           that Merrimack Station could emit                       those terms been in place at the time                  critical emission value, to provide for
                                           constantly at the mass-based emission                   and assuming that all data points                      attainment of the 1-hour NAAQS. EPA
                                           value for each of those six hours and the               flagged as calculated or substitute data               has conducted analyses to evaluate the
                                           area would attain the standard.                         are actual emissions. Of the 27 7-day                  extent to which longer-term average


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                                           25930               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           limits that have been adjusted to have                  meteorology conducive to having                        future operations at Merrimack Station.
                                           comparable stringency to 1-hour limits                  exceedances to have the average of the                 The commenter stated that the State did
                                           at the critical emission value provide for              99th percentile daily maximum values                   not disclose the nature of data
                                           attainment. In brief, while a longer-term               exceed the NAAQS. Viewed another                       corrections provided by the Merrimack
                                           average limit as approved in this action                way, the occasions when the                            Station’s owner at the time PSNH in
                                           will allow occasions when emissions                     meteorology is conducive for the source                documentation accompanying the
                                           exceed the critical emission value, the                 to cause an exceedance at a particular                 proposed permit for the facility. The
                                           use of a lower limit (i.e., as adjusted                 location are likely to be infrequent, and              commenter indicated that the
                                           downward) compensates by requiring                      high concentrations are contingent on                  nondisclosure regarding the nature of
                                           most values to be lower than they are                   both emissions being sufficiently high                 the corrections raises concerns about the
                                           required to be with a 1-hour limit at the               and the meteorology being sufficiently                 accuracy of the State’s analysis. For
                                           critical emission value. EPA expects                    conducive. The NAAQS itself is based                   future operations, the commenter points
                                           that the net result for this action will be             on relatively rare occurrences, being                  to New Hampshire’s projection of
                                           that the comparably stringent limit will                based on the 99th percentile of daily                  Merrimack Station’s annual emissions
                                           provide a sufficient constraint on the                  maximum concentrations. Nevertheless,                  for 2018 of 1,907 tons SO2, which is
                                           frequency and magnitude of occurrences                  the point here is that the occurrence of               nearly double the annual emissions total
                                           of elevated emissions such that this                    high emissions will not cause an                       of 1,044 tons SO2 for the facility in
                                           control strategy based on the                           exceedance if it does not occur when                   2014. The commenter asserts that the
                                           comparably stringent limit will                         meteorology is conducive to having an                  time period selected for developing the
                                           reasonably provide for attainment.                      exceedance. Furthermore, a source with                 adjustment factor is arbitrary and not
                                              As stated in appendix B of EPA’s                     rare occurrences of high emissions and                 representative of expected future
                                           April 2014 guidance, the Agency                         with much more frequent occurrences of                 operations, and that therefore the State
                                           acknowledges that even with an                          moderate emissions is more likely to                   should have selected a different time
                                           adjustment to provide comparable                        have moderate emissions on those                       period. The commenter identified
                                           stringency, a source complying with a                   occasions with meteorology conducive                   ‘‘significant spikes’’ in hourly emissions
                                           longer term average emission limit                      for exceedances, and the design value                  in the months before or after the time
                                           could possibly have hourly emissions                    for the source may be more prone to                    period selected by the State that are not
                                           which occasionally exceed the critical                  reflect the moderate emissions than the                included in the State’s emissions
                                           emission value. It is important to                      high emissions.                                        database. The commenter suggested that
                                           recognize that an hour where emissions                     Thus, for a source complying with a                 these emission ‘‘spikes’’ are
                                           are above the critical value does not                   limit using an averaging period of up to               inappropriately excluded, and as a
                                           necessarily mean that a NAAQS                           30 days reflecting the downward                        result the State’s results are likely to be
                                           exceedance is occurring in that hour.                   adjustment generally recommended in                    skewed. The commenter provides
                                           EPA’s April 2014 guidance states that                   EPA’s April 2014 guidance, at issue is                 several alternative adjustment factors
                                           ‘‘if periods of hourly emissions above                  the likelihood that the source would                   based on different time periods that
                                           the critical emission value are a rare                  have sufficiently high emissions on a                  include periods with emission ‘‘spikes,’’
                                           occurrence at a source, these periods                   sufficient fraction of the potential                   including an adjustment factor for each
                                           would be unlikely to have a significant                 exceedance days to cause an SO2                        year from 2012 through 2015; the period
                                           impact on air quality, insofar as they                  NAAQS violation. Although results will                 of July 4, 2013 through March 30, 2015,
                                           would be very unlikely to occur                         differ according to individual                         used by the State in its analysis; and the
                                           repeatedly at the times when the                        circumstances, EPA has presented                       25-month period from March 1, 2013
                                           meteorology is conducive for high                       illustrative analyses (see appendix B of               through March 30, 2015. The alternative
                                           ambient concentrations of SO2’’ (p. 24).                EPA’s April 2014 guidance) that
                                              Exceedances of the SO2 NAAQS occur                                                                          adjustment factors for these periods vary
                                                                                                   indicate that suitably adjusted longer-                from 0.34 to 0.90, which would result in
                                           when emissions from relevant sources                    term average limits can generally be
                                           are sufficiently high on occasions when                                                                        associated 7-day limits of between 0.19
                                                                                                   expected to provide adequate                           to 0.48 lb/MMBtu. The commenter
                                           the meteorology is conducive for those                  confidence that the attainment plan will
                                           emissions to cause elevated SO2                                                                                states that selecting the wrong time
                                                                                                   provide for attainment.                                period for analysis can result in a more
                                           concentrations. An illustrative example                    Therefore, based on the reasoning
                                           would be a case in which a single                                                                              than doubling of the resulting emission
                                                                                                   presented above, EPA disagrees with the
                                           source has a dominant impact on area                                                                           rate. The commenter concludes that the
                                                                                                   commenter about the over 224 hours
                                           concentrations, and the source only                                                                            methodology New Hampshire used for
                                                                                                   with emissions purported to be higher
                                           causes an exceedance at a particular                                                                           developing a 7-day emission rate is
                                                                                                   than the critical emission rate, and
                                           location with light southwest winds                                                                            inadequate because the adjustment
                                                                                                   concludes that the longer-term limit for
                                           with limited dispersion. In this                                                                               factor depends greatly on which
                                                                                                   Merrimack Station is not expected to
                                           example, the likelihood of an                                                                                  temporal series of emissions data is
                                                                                                   lead to a greater risk of a future violation
                                           exceedance at that location will be a                                                                          examined.
                                                                                                   of the NAAQS.
                                           function of the likelihood of elevated                     Comment 3: The commenter stated                        Response 3: EPA analyzed the
                                           emissions occurring during times of                     that New Hampshire’s approach to                       commenter’s assertion regarding
                                           light southwest winds with limited                      develop a longer-term averaging period                 variability in adjustment factors based
                                           dispersion. Stated more generally, the                  using an ‘‘adjustment ratio’’ is                       on the time period selected. An
                                           likelihood of an exceedance is a                        problematic.6 Specifically, the                        adjustment factor is a value multiplied
                                           function of the likelihood of emissions                                                                        by the 1-hour critical emission value
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                                                                                                   commenter posits that the period of
                                           being high when the meteorology is                      time selected by the State (i.e., July 4,              (i.e., the maximum 1-hour emission
                                           conducive for the source to cause an                    2013 through March 30, 2015) is not                    value established to be protective of the
                                           exceedance. By extension, the                           representative of current or expected                  NAAQS) to determine a downwardly
                                           likelihood of a violation is a function of                                                                     adjusted longer-term average limit for an
                                           the likelihood of emissions being high                    6 EPA terms these ratio values ‘‘adjustment          emission unit at a level that EPA would
                                           on a sufficient number of times with                    factors.’’                                             expect to be comparably stringent to a


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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                            25931

                                           1-hour limit set at the critical emission               response to comments document to                       critical emission value to have
                                           value.                                                  permit TP–0189 (included in New                        stringency comparable to a 1-hour limit
                                              As stated in EPA’s April 2014                        Hampshire’s Finding of Fact document),                 at the critical emission value. The State
                                           guidance, we expect that establishing an                which was also included in the State’s                 multiplied its adjustment factor of 0.73
                                           appropriate longer-term average limit                   SIP submittal. Specifically, New                       to the critical emission rate of 0.54 lb/
                                           will involve assessing a downward                       Hampshire justified the removal of                     MMBtu to derive a comparably stringent
                                           adjustment in the level of the limit that               several data points because of quality                 emission rate of 0.39 lb/MMBtu. EPA
                                           would provide for comparable                            assurance issues. The State indicated in               has confirmed that the State
                                           stringency. This assessment should                      its response to comments document that                 appropriately implemented the
                                           generally be conducted using data                       substitute data was included within the                recommended methodology for
                                           obtained by CEMS, in order to have                      AMPD dataset for hours with emissions                  developing an adjustment factor based
                                           sufficient data to obtain a robust and                  at levels the CEMS had not been                        on the State’s supplied dataset. EPA
                                           reliable assessment of the anticipated                  appropriately maintained and quality                   notes that this emission database does
                                           relationship between longer-term                        assured to measure. The State indicated                include hours representative of startup
                                           average emissions and 1-hour emission                   and EPA agrees that these substitute                   and shutdown conditions, as well as
                                           values. This is necessary to have a                     emission data are not representative of                hours with elevated emissions or
                                           suitable assessment of the warranted                    actual emissions. According to the                     ‘‘spikes.’’
                                           degree of adjustment of the longer-term                 State’s SIP submittal, the SO2 dual span                  There were five individual alternative
                                           average limit in order to provide                       analyzer in the CEMS was adjusted as                   adjustment factors for Merrimack
                                           comparable stringency to the 1-hour                     of February 4, 2015, to better                         Station presented by the commenter as
                                           emission rate that is determined to                     characterize both lower- and higher-end                evidence that EPA’s methodology
                                           provide for attainment. EPA generally                   emissions. In its response to comments,                (including adjustment factors) is not
                                           expects that datasets reflecting hourly                 the State provided an hour-by-hour                     appropriate for developing emissions
                                           data for at least 3 to 5 years of stable                listing of the omitted data points, and a              limitations based on averaging times for
                                           operation (i.e., without changes that                   detailed discussion of the reasoning for               periods up to 30 days. Four of the five
                                           significantly alter emissions variability)              these omissions. The State’s Findings of               alternative adjustment factors presented
                                           would be needed to conduct a suitably                   Fact document is included in the docket
                                                                                                                                                          by the commenter are based upon only
                                           reliable analysis.                                      for this action. As such, EPA notes that
                                              For Merrimack Station, at the time                                                                          one year of emissions data for each of
                                                                                                   New Hampshire sufficiently provided
                                           that New Hampshire had conducted its                                                                           the annual periods of 2012 through
                                                                                                   its rationale and approach for removing
                                           analysis, only approximately 21 months                                                                         2015. One of the periods presented
                                                                                                   certain data points from the AMPD
                                           of emissions data were available that                                                                          includes emissions over a period of 25
                                                                                                   dataset in the State’s response to
                                           were consistent with anticipated current                                                                       months, specifically for the period from
                                                                                                   comments document. Therefore, EPA
                                           and future operations. Specifically, the                                                                       March 2013 through March 2015
                                                                                                   concludes that the State has
                                           emissions units at Merrimack Station                                                                           resulting in an alternative adjustment
                                                                                                   appropriately disclosed the nature of the
                                           became subject to certain enforceable                                                                          factor of 0.47, compared to the State’s
                                                                                                   data corrections in the State’s SIP
                                           conditions contained in permit number                   submittal, and that the public has had                 adjustment factor of 0.73 based on the
                                           TP–0008 beginning on July 1, 2013.                      adequate notice and opportunity to                     21-month time period of July 2013
                                           Thus, emissions from Merrimack                          comment on the State’s justification for               through March 2015. None of the
                                           Station prior to July 1, 2013 are not                   data removal in the current rulemaking                 alternative adjustment factors provided
                                           expected to have an emissions profile                   process. EPA has placed the raw data                   by the commenter were calculated in
                                           consistent with the current and                         that New Hampshire used in the docket                  accordance with the recommendations
                                           anticipated future emissions profile for                for this action, but EPA asserts that the              contained in EPA’s April 2014
                                           those units. March 2015 was selected by                 information provided by the State and                  guidance. Specifically, EPA stated in its
                                           the State as the end point of the                       by EPA in its proposal was adequate to                 April 2014 guidance ‘‘that data sets
                                           emissions dataset because it was the last               clarify EPA’s rationale for concurring                 reflecting hourly data for at least 3 to 5
                                           month in which data were available                      with the State’s analysis of the data.                 years of stable operation (i.e., without
                                           through AMPD at the time it conducted                      Regarding the omission of calculated                changes that significantly alter
                                           the analysis. During the period assessed                or substitute data, the calculated or                  emissions variability) would be needed
                                           by the State, the combined emissions                    substitute data points are not reliable                to obtain a suitably reliable analysis’’ (p.
                                           from Merrimack Station’s units MK1                      indicators of emissions during those                   30). Furthermore, the alternative
                                           and MK2 were always controlled by                       hours and are not appropriate for                      adjustment factors for March 2013
                                           FGD and the dataset includes emissions                  inclusion in the calculation of the                    through March 2015 and the annual
                                           representative of current and expected                  adjustment factor. Based on this                       periods for 2012 and 2013 as presented
                                           future typical operations, including                    reasoning, EPA considers the State’s                   by the commenter include periods of
                                           startup and shutdown events. Because                    omission of these values in the                        time (i.e., those prior to July 1, 2013
                                           the dataset includes only data from                     calculation of the adjustment factor to                when FGD use was not an enforceable
                                           Merrimack Station while using the                       be appropriate.                                        State permit condition) during which
                                           control technology, it is appropriate for                  The adjustment factor was calculated                operations are not representative of
                                           use in developing adjustment factors for                as the ratio of the 99th percentile of                 current and expected future operations
                                           emission limits at this facility. EPA has               mass emissions for the 7-day average                   at Merrimack Station, as discussed in
                                           concluded that New Hampshire used                       period to the 99th percentile of 1-hour                greater detail in our response to
                                           data from an appropriate time period.                   mass emissions. For the rolling 7-day                  Comment 2 of the notice. The remaining
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                                              Prior to deriving the adjustment                     averaging period, the adjustment factor                alternative adjustment factors that do
                                           factor, the State removed several data                  was 0.73. That is, using EPA’s                         not contain periods of time prior to July
                                           points from the AMPD dataset based on                   recommended approach for determining                   1, 2013, i.e., the annual periods for 2014
                                           information provided by the facility. A                 comparably stringent limits, the 7-day                 and 2015, are 0.90 and 0.70,
                                           justification for removal of these data                 mass emission rate limit would need to                 respectively, which are reasonably
                                           points was included in the State’s                      be 0.73 times (or 27% lower than) the                  consistent with the State’s finding based


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                                           25932               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           on a larger dataset. However, the                       in the State’s SIP submittal.                          defined as a receptor grid network or
                                           commenter’s results illustrate a point                  Nevertheless, this projected increase in               grid. The primary purpose of this
                                           that EPA considered in formulating its                  annual emissions does not, however,                    network or grid is to locate the
                                           guidance, which is that using                           indicate a different emissions profile.                maximum impact of concern per
                                           insufficient data, e.g., using only one                 That is, based on available information,               pollutant and averaging period.
                                           year’s data, is prone to yield results that             EPA does not expect an increase in the                 Deciding which type to use is largely a
                                           vary unduly by data period and may not                  variability of hourly emissions due to an              function of the type of modeling being
                                           be a sufficiently robust basis for                      increase in annual emissions. In fact,                 performed (screening or refined), the
                                           determining a reliable adjustment factor.               the attainment demonstration included                  size and number of emission sources, or
                                           The variability of these annual values                  in New Hampshire’s SIP submittal                       the site location (including topography),
                                           demonstrates the insufficiency of the                   indicates that annual SO2 emissions at                 and should be selected to provide the
                                           annual time period for use in                           the critical emission value, equivalent to             best ‘‘coverage’’ for the facility being
                                           development of such an adjustment                       annual emissions of 11,144 tons, is                    modeled. Two types of receptors are
                                           factor, but does not demonstrate the                    anticipated to be protective of the 2010               generally employed: (1) A Cartesian
                                           insufficiency of the method contained                   SO2 NAAQS. The State’s comparably                      receptor grid, which consists of
                                           within EPA’s April 2014 guidance had                    stringent 7-day average limit of 0.39 lb/              receptors identified by their x (east-
                                           it been appropriately applied, nor does                 MMBtu equates to total annual SO2                      west) and y (north-south) coordinates;
                                           it demonstrate that New Hampshire’s                     emissions of 8,047 tons. Both values are               and (2) a polar receptor grid that
                                           adjustment factor is inappropriate.                     above the State’s 2018 projected                       consists of receptors identified by their
                                              EPA recognizes that the State used 21                emissions of 1,927 tons. Because New                   distance and direction (angle) from a
                                           months in its emissions variability                     Hampshire’s attainment demonstration                   user defined origin (e.g., main boiler
                                           analysis instead of the 3 to 5 years                    shows that the critical emission value is              stack). Discrete receptors are used to
                                           recommended for use in EPA’s April                      protective of the NAAQS, and the                       identify specific locations of interest
                                           2014 guidance. As such, EPA has                         State’s 7-day limit is comparably                      (e.g., school, community building). A
                                           evaluated whether the period used by                    stringent to the 1-hour critical emission              modeling receptor grid may consist of
                                           the State results in an appropriate                     value, EPA concludes that the State’s                  any combination of discrete, polar, or
                                           adjustment factor. Specifically, EPA                    projected 85% increase in annual SO2                   Cartesian receptors, but must provide
                                           compared the State’s adjustment factor                  emissions from 2014 to 2018 would not                  sufficient detail and resolution to
                                           to EPA’s average 30-day adjustment                      result in a violation of the NAAQS.                    identify the maximum impact.
                                           factor for comparable sources.                             Therefore, based on the reasoning                      On October 30, 2015, the State
                                           Merrimack Station’s FGD system                          presented above, EPA has concluded                     submitted preliminary modeling to EPA
                                           employs a wet scrubber, and so EPA                      that the commenter has not                             for the attainment demonstration for the
                                           compared New Hampshire’s adjustment                     demonstrated that the State developed                  Central New Hampshire Nonattainment
                                           factor to the average adjustment factors                its adjustment factor for Merrimack                    Area. EPA responded on January 6,
                                           listed in appendix D of the April 2014                  Station inappropriately, or that the                   2016, to the State’s preliminary
                                           guidance for sources with wet scrubbers                 State’s 7-day limit for Merrimack                      modeling submittal. In EPA’s response,
                                           (derived from a database of 210                         Station derived using the adjustment                   the Agency indicated that section
                                           sources). For this set of sources, EPA                  factor is inadequate.                                  4.2.1.2(b) of the Guideline 7 describes
                                           calculated an average adjustment factor                    Comment 4: The commenter indicates
                                                                                                                                                          the process for performing screening
                                           for 30-day average limits of 0.71 and an                that the polar receptor grid used by the
                                                                                                                                                          modeling in areas with complex terrain.
                                           average adjustment factor for 24-hour                   State in its modeling analysis is
                                                                                                   inadequate because of the small overall                As stated in our letter, in areas with
                                           limits of 0.89. The comparison of New
                                                                                                   number of receptors and lack of                        complex terrain, ‘‘even relatively small
                                           Hampshire’s adjustment factor of 0.73
                                                                                                   coverage over large areas of land. The                 changes in a receptor’s location may
                                           for a 7-day limit for Merrimack Station
                                                                                                   commenter states that the polar grid                   substantially affect the predicted
                                           suggests that the 21 months of data at
                                                                                                   ensures that the model will                            concentration.’’ The Guideline
                                           Merrimack Station have variability that
                                                                                                   underpredict concentrations due to                     recommended a dense array of receptors
                                           is quite similar to that of other similar
                                                                                                   these ‘‘blind spots,’’ areas where there               in those situations, and suggests two
                                           facilities in the United States. Based on
                                                                                                   are no receptors and which the model                   modeling runs: the first with ‘‘a
                                           this comparison, EPA concludes that the
                                           State’s adjustment factor is reasonable                 will overlook when the wind is blowing                 moderate number of receptors carefully
                                           and will result in an appropriate                       in their direction across the sources.                 located over the area of interest,’’ and a
                                           downward adjustment from the critical                   Because the model is ultimately the                    second with ‘‘a more dense array of
                                           emission value.                                         basis for the development of the                       receptors in areas showing potential for
                                              Based on the State’s SIP submittal,                  emissions limit for Merrimack Station,                 high concentrations, as indicated by the
                                           New Hampshire’s future projection of                    the commenter posits that the polar                    results of the first model run.’’ This
                                           SO2 emissions at Merrimack Station to                   receptor grid with contiguous radial                   process is also consistent with section
                                           2018 indicates an increase of nearly                    coverage gaps is improper.                             7.2.2 (Critical Receptor Sites) of the
                                           85% compared to 2014 emissions for                         Response 4: EPA agrees with the                     Guideline, which states that ‘‘selection
                                           the facility. Specifically, Tables 5–1B                 commenter that simple polar grids alone                of receptor sites should be a case-by-
                                           and 5–2B of the State’s SIP submittal                   may not be appropriate for use without                 case determination taking into
                                           indicate that Merrimack Station’s SO2                   refinement in refined modeling                         consideration the topography, the
                                           emissions were 1,044 tons in 2014 and                   analyses, though inclusion of a polar                  climatology, monitor sites, and the
                                           are projected to be 1,927 tons in 2018.                 receptor grid does not in and of itself                results of the initial screening
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                                           The emission projection for 2018                        disqualify an attainment demonstration.                procedure.’’ In our letter to New
                                           includes the caveat from the State that                    Receptors are points that represent
                                                                                                                                                            7 At the time of EPA’s January 6, 2016 letter to
                                           it relies on an assumed control                         physical locations at which the air
                                                                                                                                                          New Hampshire, the update to the Guideline had
                                           efficiency for the FGD of 90%, which is                 dispersion models will predict ambient                 not yet been finalized and was not in effect.
                                           less efficient than the updated control                 pollutant concentrations. Groups of                    Therefore, the applicable Guideline was the version
                                           efficiency of 94% for the FGD included                  Cartesian or polar receptors usually are               published on November 9, 2005 (see 70 FR 68218).



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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                          25933

                                           Hampshire, EPA noted that the                           most cases, maximum source impacts of                  modeling analyses are also required.
                                           preliminary modeling results (i.e., those               inert pollutants will occur within the                 The commenter asserts that the
                                           presented to the Agency on October 30,                  first 10 to 20 km from the source.’’                   statement should be removed from the
                                           2015) showed maximum concentrations                     Furthermore, EPA’s review of both the                  State’s SIP submittal.
                                           resulting from Merrimack Station’s SO2                  preliminary and refined modeling                          Response 6: The State indicated in its
                                           emissions in areas of complex terrain                   indicate that these areas of complex                   response to an identical comment on its
                                           between 9 to 13 kilometers from                         terrain are likely to include the highest              draft SIP submittal that it planned to
                                           Merrimack Station. EPA stated that the                  impact area. Therefore, EPA finds that                 remove the phrase ‘‘and thus may be
                                           polar receptor grid at those distances                  the modeling domain and receptor                       able to demonstrate attainment for the
                                           from the source were insufficiently                     network are sufficient to identify                     SO2 NAAQS’’ from Section 3.1.1 on
                                           dense to properly characterize the                      maximum impacts from Merrimack                         page 9 of its SIP submittal. In doing so,
                                           extent of the impacts at locations with                 Station, and are therefore adequate for                the State would be satisfying the request
                                           complex terrain. For example, at 13                     characterizing the nonattainment area.                 made by the commenter. However, the
                                           kilometers from the source, the lateral                    Comment 5: The commenter pointed                    erroneous phrase still appeared in the
                                           distance between receptors is greater                   out an error in Table 3–1 of the State’s               State’s January 31, 2017 SIP submittal to
                                           than 2 kilometers. EPA also indicated                   draft SIP submittal. Specifically, the                 EPA. EPA agrees with the commenter
                                           that other locations with similar terrain               commenter indicated that Table 3–1                     that the phrase is incorrect and ought
                                           characteristics in the same general                     incorrectly showed areas that are                      not to be in the plan. EPA
                                           distance (i.e., 9–13 kilometers) from                   undesignated in New Hampshire as                       communicated with the State to confirm
                                           Merrimack Station did not have                          being designated Unclassifiable. The                   that it had intended to remove the
                                           adequate receptor coverage. To address                  commenter indicated that those areas                   phrase as indicated by the State’s
                                           this issue, EPA suggested in its January                should instead be identified as                        response to comments on its draft SIP
                                           6, 2016 letter, that New Hampshire                      undesignated.                                          submittal, and to suggest a clarification.
                                           perform refined modeling consistent                        Response 5: EPA agrees with the                     On November 29, 2017, New Hampshire
                                           with its existing protocol, but with a                  commenter that all areas in New                        sent EPA a letter indicating that the
                                           denser array of receptors in the areas                  Hampshire other than the Central New                   language had been erroneously included
                                           shown in the preliminary modeling to                    Hampshire Nonattainment Area were                      in its January 31, 2017 submittal, and
                                           have the potential for high                             undesignated as of the date of New                     providing a corrected page 9 of the
                                           concentrations. Specifically, areas of                  Hampshire’s submittal (i.e., January 31,               State’s SIP submittal. EPA considers this
                                           complex terrain at distances within 15                  2017). In its response to this identical               amended version (i.e., the January 31,
                                           kilometers of Merrimack Station, and                    comment on its proposed SIP submittal,                 2017, submittal as amended by the
                                                                                                   the State indicated that Table 3–1 had                 November 29, 2017, correction on page
                                           particularly such areas to the northeast,
                                                                                                   been corrected. EPA has verified that                  9) to be consistent with the State’s
                                           were suggested by EPA to be modeled
                                                                                                   the State did indeed correct the table.                record, as included in its response to
                                           with high resolution receptor grids. EPA
                                                                                                   EPA notes that revised                                 comments.
                                           listed these areas and provided a map of
                                                                                                   recommendations from New Hampshire                        Comment 7: The commenter identifies
                                           these areas to the State. EPA indicated
                                                                                                   other than those listed in Table 3–1                   an error in Table 5–1B of the State’s
                                           that these terrain features have the
                                                                                                   were received by EPA in December                       draft SIP submittal. Specifically, the
                                           potential to be highly impacted by
                                                                                                   2016, specifically for attainment at the               commenter indicates that the table
                                           Merrimack Station because of their
                                                                                                   New Hampshire Seacoast area and                        erroneously states that the total
                                           geographic characteristics and locations,
                                                                                                   attainment/unclassifiable for all other                estimated emissions for the Central New
                                           but were not well characterized by the                  previously undesignated areas.                         Hampshire Nonattainment Area for
                                           preliminary modeling due to the                         Furthermore, on January 9, 2018, EPA                   2014 was 22,947 tons of SO2. The
                                           sparseness of the polar grid at distances               published a document of a final rule                   commenter further states that the proper
                                           beyond around 5 kilometers.                             that designated all areas in New                       total for 2014 emissions should be 1,480
                                              In response to EPA’s January 2016,                   Hampshire other than the Central New                   tons of SO2. The commenter indicates
                                           letter, the State included additional                   Hampshire Nonattainment Area as                        that the figure is assumed to be an error
                                           receptors in these areas for its refined                attainment/unclassifiable (see 83 FR                   that should be corrected.
                                           modeling conducted in February 2016.                    1098, 1143, to be codified at 40 CFR                      Response 7: EPA agrees with the
                                           Specifically, New Hampshire included                    81.330). These inconsistencies in Table                commenter that the total 2014 emissions
                                           2,308 additional receptors in dense                     3–1 with subsequent occurrences have                   within the Central New Hampshire
                                           Cartesian arrays with 100-meter spatial                 to do with the timing of the SIP                       Nonattainment Area should be 1,480
                                           resolution over the areas of expected                   submittal along with the December 2016                 tons SO2. The commenter had supplied
                                           maximum predicted concentrations                        update to the State’s recommendations                  an identical comment on New
                                           based on preliminary modeling,                          and EPA’s January 9, 2018 final                        Hampshire’s draft SIP submittal, and the
                                           including over the areas suggested by                   designations. These inconsistencies do                 State’s response to comment document
                                           EPA within 5–15 kilometers from                         not affect EPA’s view of whether New                   included in its final SIP submittal stated
                                           Merrimack Station. After reviewing the                  Hampshire has satisfied applicable                     that the error would be corrected. As
                                           receptor grid included by the State in its              nonattainment planning requirements.                   indicated by the State in its response to
                                           refined modeling, EPA concludes that                       Comment 6: The commenter states                     comments, Table 5–1B shows the
                                           areas of complex terrain within 15                      that the State’s SIP submittal incorrectly             corrected value. As such, EPA considers
                                           kilometers have adequate coverage to                    indicates that an attainment                           this comment to have been already
                                           identify potential impacts in those                     demonstration can be made based on                     addressed by the State.
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                                           areas. This conclusion is consistent with               monitor readings alone. This idea is                      Comment 8: In the incorporated
                                           the statement in section 4 (Models for                  contrary to other statements in the                    comments dated July 15, 2016, the
                                           Carbon Monoxide, Lead, Sulfur Dioxide,                  State’s SIP submittal, and also to EPA’s               commenter states that New Hampshire
                                           Nitrogen Dioxide and Primary                            April 2014 guidance, which states that                 is long overdue for finalizing a plan to
                                           Particulate Matter) of the Guideline                    monitor data alone is insufficient for an              ensure attainment and maintenance of
                                           (specifically section 4.2(a)) that ‘‘[i]n               attainment demonstration, and that                     the SO2 NAAQS. The commenter goes


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                                           25934               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           on to state that the (then) proposed                    recordkeeping, and reporting                           Requirements’’); items 1 and 2 in Table
                                           permit is apparently only a step towards                requirements contained in Merrimack                    6 (‘‘Recordkeeping Requirements’’); and
                                           developing such a SIP. The commenter                    Station’s permit, TP–0189, to                          items 1 and 2 in Table 7 (‘‘Reporting
                                           concludes by urging the State to swiftly                demonstrate how compliance with                        Requirements’’). EPA has made, and
                                           address the issues identified in its                    Merrimack Station’s SO2 emission limit                 will continue to make, relevant
                                           comments on the proposed permit for                     will be achieved and determined. EPA                   documents, including the portions of
                                           Merrimack Station.                                      is approving into the New Hampshire                    TP–0189 being incorporated by
                                              Response 8: There are two plausible                  SIP the provisions of Merrimack                        reference, generally available through
                                           interpretations of this comment. The                    Station’s permit, TP–0189, that                        www.regulations.gov.
                                           first interpretation is procedural.                     constitute the SO2 operating and
                                           Interpreted in this fashion, the                                                                               V. Statutory and Executive Order
                                                                                                   emission limits and their associated
                                           commenter would be requesting that the                                                                         Reviews
                                                                                                   monitoring, testing, recordkeeping, and
                                           permitting authority expedite the                       reporting requirements. EPA is                            Under the Clean Air Act, the
                                           permitting for Merrimack Station, which                 approving these provisions into the                    Administrator is required to approve a
                                           would be a critical component of the                    State’s SIP through incorporation by                   SIP submission that complies with the
                                           anticipated attainment plan for the area                reference, as described in section IV.,                provisions of the Act and applicable
                                           around Merrimack Station. Interpreted                   below.                                                 Federal regulations. 42 U.S.C. 7410(k);
                                           this first way, the comment is addressed                   EPA is not removing the portion of                  40 CFR 52.02(a). Thus, in reviewing SIP
                                           through the current action, which is the                the New Hampshire SIP entitled ‘‘EPA-                  submissions, EPA’s role is to approve
                                           final step in the procedure for approving               approved State Source specific                         state choices, provided that they meet
                                           an attainment plan for the area. A                      requirements’’ as it pertains to                       the criteria of the Clean Air Act.
                                           second interpretation implies technical                 Merrimack Station’s July 2011 permit,                  Accordingly, this action merely
                                           insufficiency. Interpreted in this                      TP–0008, because EPA did not receive                   approves state law as meeting Federal
                                           fashion, the commenter would be                         a request from the State to do so. See 40              requirements and does not impose
                                           indicating that the proposed permit,                    CFR 52.1520(d). However, EPA                           additional requirements beyond those
                                           when finalized, would be just one of                    considers those provisions to be                       imposed by state law. For that reason,
                                           multiple required actions necessary to                  superseded by the conditions of TP–                    this action:
                                           ensure attainment in the nonattainment                  0189, which are more stringent, and                       • Is not a significant regulatory action
                                           area. Interpreted this second way, the                  which are being incorporated into the                  subject to review by the Office of
                                           comment rests on the previous                           SIP in this final action. Specifically, two            Management and Budget under
                                           arguments provided by the commenter                     of the provisions, items 6 and 8 from                  Executive Orders 12866 (58 FR 51735,
                                           suggesting that the State’s proposed                    Table 4, relate to SO2 emissions limits                October 4, 1993) and 13563 (76 FR 3821,
                                           plan does not ensure attainment of the                  that have been superseded by                           January 21, 2011);
                                           NAAQS. On these grounds, EPA                            Merrimack Station’s September 2016                        • does not impose an information
                                           disagrees with the commenter that the                   permit, TP–0189. Item 10 from Table 4                  collection burden under the provisions
                                           proposed nonattainment area plan may                    has also been superseded by Merrimack                  of the Paperwork Reduction Act (44
                                           be insufficient to ensure attainment.                   Station’s September 2016 permit, TP–                   U.S.C. 3501 et seq.);
                                           EPA has provided ample discussion and                   0189, in that the existing SIP provision                  • is certified as not having a
                                           evidence, in both the current response                  allowed operation of one of Merrimack                  significant economic impact on a
                                           to comments and the September 28,                       Station’s two boilers, MK1, for up to 840              substantial number of small entities
                                           2017 proposal, for why the State’s                      hours in any consecutive 12-month                      under the Regulatory Flexibility Act (5
                                           nonattainment plan and SO2 attainment                   period through the emergency bypass                    U.S.C. 601 et seq.);
                                           demonstration are sufficient.                           stack, i.e., not through the FGD system.                  • does not contain any unfunded
                                                                                                   Each of the corresponding provisions of                mandate or significantly or uniquely
                                           III. Final Action
                                                                                                   Merrimack Station’s September 2016                     affect small governments, as described
                                              EPA has determined that New                          permit, TP–0189, are more stringent                    in the Unfunded Mandates Reform Act
                                           Hampshire’s SO2 nonattainment plan                      than those existing SIP provisions. The                of 1995 (Pub. L. 104–4);
                                           meets the applicable requirements of                    limits EPA is approving into New                          • does not have Federalism
                                           sections 110, 172, 191, and 192 of the                  Hampshire’s SIP in this action do not                  implications as specified in Executive
                                           CAA. EPA is approving New                               exempt any hours from being subject to                 Order 13132 (64 FR 43255, August 10,
                                           Hampshire’s January 31, 2017 SIP                        the limit.                                             1999);
                                           submission, as amended by the State on                                                                            • is not an economically significant
                                           November 29, 2017, for attaining the                    IV. Incorporation by Reference
                                                                                                                                                          regulatory action based on health or
                                           2010 primary 1-hour SO2 NAAQS for                         In this rule, EPA is finalizing                      safety risks subject to Executive Order
                                           the Central New Hampshire                               regulatory text that includes                          13045 (62 FR 19885, April 23, 1997);
                                           Nonattainment Area and for meeting                      incorporation by reference. In                            • is not a significant regulatory action
                                           other nonattainment area planning                       accordance with requirements of 1 CFR                  subject to Executive Order 13211 (66 FR
                                           requirements. This SO2 nonattainment                    51.5, EPA is finalizing the incorporation              28355, May 22, 2001);
                                           plan includes New Hampshire’s                           by reference of certain federally                         • is not subject to requirements of
                                           attainment demonstration for the SO2                    enforceable provisions of Merrimack                    Section 12(d) of the National
                                           nonattainment area. The nonattainment                   Station’s permit, TP–0189, effective on                Technology Transfer and Advancement
                                           area plan also addresses requirements                   September 1, 2016, described in the                    Act of 1995 (15 U.S.C. 272 note) because
                                           for RFP, RACT/RACM, enforceable                         amendments to 40 CFR part 52 set forth                 application of those requirements would
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                                           emission limits and control measures,                   below. Specifically, the following                     be inconsistent with the Clean Air Act;
                                           base-year and projection-year emission                  provisions of that permit are                          and
                                           inventories, and contingency measures.                  incorporated by reference: Items 1, 2,                    • does not provide EPA with the
                                              In New Hampshire’s SIP submittal to                  and 3 in Table 4 (‘‘Operating and                      discretionary authority to address, as
                                           EPA, New Hampshire included the                         Emission Limits’’); items 1 and 2 in                   appropriate, disproportionate human
                                           applicable monitoring, testing,                         Table 5 (‘‘Monitoring and Testing                      health or environmental effects, using


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                                                               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations                                                              25935

                                           practicable and legally permissible                      This action is not a ‘‘major rule’’ as                          PART 52—APPROVAL AND
                                           methods, under Executive Order 12898                     defined by 5 U.S.C. 804(2).                                     PROMULGATION OF
                                           (59 FR 7629, February 16, 1994).                            Under section 307(b)(1) of the Clean                         IMPLEMENTATION PLANS
                                              In addition, the SIP is not approved                  Air Act, petitions for judicial review of
                                           to apply on any Indian reservation land                  this action must be filed in the United                         ■ 1. The authority citation for part 52
                                           or in any other area where EPA or an                     States Court of Appeals for the                                 continues to read as follows:
                                           Indian tribe has demonstrated that a                     appropriate circuit by August 6, 2018.
                                           tribe has jurisdiction. In those areas of                Filing a petition for reconsideration by                            Authority: 42 U.S.C. 7401 et seq.
                                           Indian country, the rule does not have                   the Administrator of this final rule does
                                           tribal implications and will not impose                  not affect the finality of this action for                      Subpart EE—New Hampshire
                                           substantial direct costs on tribal                       the purposes of judicial review nor does
                                           governments or preempt tribal law as                     it extend the time within which a                               ■ 2. Section 52.1520 is amended:
                                           specified by Executive Order 13175 (65                   petition for judicial review may be filed,                      ■ a. In the table in paragraph (d) by:
                                           FR 67249, November 9, 2000).                             and shall not postpone the effectiveness                        ■ i. Revising the entry for ‘‘PSNH
                                              The Congressional Review Act, 5                       of such rule or action. This action may
                                           U.S.C. 801 et seq., as added by the Small                                                                                Merrimack Station’’; and
                                                                                                    not be challenged later in proceedings to
                                           Business Regulatory Enforcement                          enforce its requirements. (See section                          ■ ii. Adding the entry for ‘‘PSNH d/b/a
                                           Fairness Act of 1996, generally provides                 307(b)(2).)                                                     Eversource Energy Merrimack Station,’’
                                           that before a rule may take effect, the                                                                                  at the end of the table; and
                                           agency promulgating the rule must                        List of Subjects in 40 CFR Part 52
                                                                                                                                                                    ■ b. In the table in paragraph (e), by
                                           submit a rule report, which includes a                     Environmental protection, Air                                 adding an entry for ‘‘Central New
                                           copy of the rule, to each House of the                   pollution control, Incorporation by
                                           Congress and to the Comptroller General                                                                                  Hampshire Nonattainment Area Plan for
                                                                                                    reference, Intergovernmental relations,
                                           of the United States. EPA will submit a                                                                                  the 2010 Primary 1-Hour Sulfur Dioxide
                                                                                                    Reporting and recordkeeping
                                           report containing this action and other                                                                                  NAAQS’’ at the end of the table.
                                                                                                    requirements, Sulfur oxides.
                                           required information to the U.S. Senate,                                                                                    The revision and additions read as
                                                                                                      Dated: May 23, 2018.
                                           the U.S. House of Representatives, and                                                                                   follows:
                                                                                                    Alexandra Dunn,
                                           the Comptroller General of the United
                                           States prior to publication of the rule in               Regional Administrator, EPA New England.                        § 52.1520    Identification of plan.
                                           the Federal Register. A major rule                         Part 52 of chapter I, title 40 of the                         *       *    *       *    *
                                           cannot take effect until 60 days after it                Code of Federal Regulations is amended                              (d) * * *
                                           is published in the Federal Register.                    as follows:

                                                                                 EPA-APPROVED NEW HAMPSHIRE SOURCE SPECIFIC REQUIREMENTS
                                                                                                  State
                                                  Name of source                 Permit No.      effective            EPA approval date           2               Additional explanations/§ 52.1535 citation
                                                                                                   date


                                                  *                    *                              *                    *                                  *                   *                   *
                                           PSNH Merrimack Station .... TP–0008 ..                  7/8/2011    8/22/2012, 77 FR 50602 ....                 Flue Gas Desulfurization System. Portions of this per-
                                                                                                                                                             mit have been superseded by TP–0189 for PSNH d/
                                                                                                                                                             b/a Eversource Energy Merrimack Station.

                                                   *                         *                        *                     *                                   *                   *                  *
                                           PSNH d/b/a Eversource En-          TP–0189 ..           9/1/2016    6/5/2018, [Insert Federal                   Items 1, 2, and 3 in Table 4 ‘‘Operating and Emission
                                            ergy Merrimack Station.                                              Register citation].                          Limits’’; items 1 and 2 in Table 5 ‘‘Monitoring and
                                                                                                                                                              Testing Requirements’’; items 1 and 2 in Table 6
                                                                                                                                                              ‘‘Recordkeeping Requirements’’; items 1 and 2 in
                                                                                                                                                              Table 7 ‘‘Reporting Requirements’’.
                                             2 In order to determine the EPA effective date for a specific provision listed in this table, consult the Federal Register notice cited in this col-
                                           umn for the particular provision.


                                              (e) * * *

                                                                                                      NEW HAMPSHIRE NONREGULATORY
                                                                                             Applicable
                                                       Name of                                                              State submittal                                          3
                                                                                     geographic or nonattainment                                              EPA approved date                   Explanations
                                              nonregulatory SIP provision                                                  date/effective date
                                                                                                area


                                                    *                    *                        *                               *                           *                  *                          *
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                                           Central New Hampshire Non-              Central New Hampshire SO2                             1/31/2017        6/5/2018 [Insert Federal Reg-
                                             attainment Area Plan for the            Nonattainment Area.                                                    ister citation].
                                             2010 Primary 1-Hour Sulfur
                                             Dioxide NAAQS.
                                             3 In order to determine the EPA effective date for a specific provision listed in this table, consult the Federal Register notice cited in this col-
                                           umn for the particular provision.



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                                           25936               Federal Register / Vol. 83, No. 108 / Tuesday, June 5, 2018 / Rules and Regulations

                                           [FR Doc. 2018–11597 Filed 6–4–18; 8:45 am]              List of Subjects                                       Corporation submitted a petition to EPA
                                           BILLING CODE 6560–50–P                                                                                         under the Federal Food, Drug, and
                                                                                                   40 CFR Part 60
                                                                                                                                                          Cosmetic Act (FFDCA), requesting
                                                                                                     Environmental protection,                            establishment of an exemption from the
                                           ENVIRONMENTAL PROTECTION                                Administrative practice and procedure,                 requirement of a tolerance. This
                                           AGENCY                                                  Air pollution control, Intergovernmental               regulation eliminates the need to
                                                                                                   relations, Reporting and recordkeeping                 establish a maximum permissible level
                                           40 CFR Parts 60, 61, and 63                             requirements.                                          for residues of ethoxylated fatty acid
                                                                                                   40 CFR Part 61                                         methyl esters when used in accordance
                                           [EPA–R06–OAR–2016–0091; FRL–9978–89–                                                                           with the terms of the exemption.
                                           Region 6]                                                 Environmental protection,                            DATES: This regulation is effective June
                                                                                                   Administrative practice and procedure,                 5, 2018. Objections and requests for
                                           New Source Performance Standards                        Air pollution control, Arsenic, Benzene,               hearings must be received on or before
                                           and National Emission Standards for                     Beryllium, Hazardous substances,                       August 6, 2018, and must be filed in
                                           Hazardous Air Pollutants; Delegation                    Intergovernmental relations, Mercury,                  accordance with the instructions
                                           of Authority to New Mexico                              Reporting and recordkeeping                            provided in 40 CFR part 178 (see also
                                                                                                   requirements, Vinyl chloride.                          Unit I.C. of the SUPPLEMENTARY
                                           AGENCY: Environmental Protection
                                                                                                   40 CFR Part 63                                         INFORMATION).
                                           Agency (EPA).
                                                                                                     Environmental protection,                            ADDRESSES: The docket for this action,
                                           ACTION:   Withdrawal of direct final rule.              Administrative practice and procedure,                 identified by docket identification (ID)
                                                                                                   Air pollution control, Hazardous                       number EPA–HQ–OPP–2017–0666, is
                                           SUMMARY:   On April 13, 2018, the                                                                              available at http://www.regulations.gov
                                                                                                   substances, Intergovernmental relations,
                                           Environmental Protection Agency (EPA)                                                                          or at the Office of Pesticide Programs
                                                                                                   Reporting and recordkeeping
                                           published a direct final rule approving                                                                        Regulatory Public Docket (OPP Docket)
                                                                                                   requirements.
                                           the updated delegation of EPA authority                                                                        in the Environmental Protection Agency
                                           for implementation and enforcement of                     Dated: May 30, 2018.
                                                                                                                                                          Docket Center (EPA/DC), West William
                                           certain New Source Performance                          Wren Stenger,
                                                                                                                                                          Jefferson Clinton Bldg., Rm. 3334, 1301
                                           Standards (NSPS) and National                           Director, Multimedia Division, Region 6.               Constitution Ave. NW, Washington, DC
                                           Emission Standards for Hazardous Air                    ■ Accordingly, the direct final rule                   20460–0001. The Public Reading Room
                                           Pollutants (NESHAPs) for all sources                    published in the Federal Register on                   is open from 8:30 a.m. to 4:30 p.m.,
                                           (both part 70 and non-part 70 sources)                  April 13, 2018 (83 FR 15964), amending                 Monday through Friday, excluding legal
                                           to the New Mexico Environmental                         40 CFR 60.4, 40 CFR 61.04, and 40 CFR                  holidays. The telephone number for the
                                           Department (NMED). EPA stated in the                    63.99, which was to become effective on                Public Reading Room is (202) 566–1744,
                                           direct final rule that if EPA received                  June 12, 2018, is withdrawn.                           and the telephone number for the OPP
                                           relevant adverse comments by May 14,                    [FR Doc. 2018–12013 Filed 6–4–18; 8:45 am]             Docket is (703) 305–5805. Please review
                                           2018, EPA would publish a timely                        BILLING CODE 6560–50–P                                 the visitor instructions and additional
                                           withdrawal in the Federal Register. EPA                                                                        information about the docket available
                                           received an adverse comment on May                                                                             at http://www.epa.gov/dockets.
                                           14, 2018, and accordingly is                            ENVIRONMENTAL PROTECTION                               FOR FURTHER INFORMATION CONTACT:
                                           withdrawing the direct final rule.                      AGENCY                                                 Michael Goodis, Registration Division
                                           DATES:The direct final rule published                                                                          (7505P), Office of Pesticide Programs,
                                                                                                   40 CFR Part 180
                                           on April 13, 2018 (83 FR 15964), is                                                                            Environmental Protection Agency, 1200
                                           withdrawn effective June 5, 2018.                       [EPA–HQ–OPP–2017–0666; FRL–9976–39]                    Pennsylvania Ave. NW, Washington, DC
                                                                                                                                                          20460–0001; main telephone number:
                                           FOR FURTHER INFORMATION CONTACT:               Mr.      Ethoxylated Fatty Acid Methyl Esters;                  (703) 305–7090; email address:
                                           Rick Barrett, (214) 665–7227,                           Exemption From the Requirement of a                    RDFRNotices@epa.gov.
                                           barrett.richard@epa.gov.                                Tolerance                                              SUPPLEMENTARY INFORMATION:
                                           SUPPLEMENTARY INFORMATION:        On April              AGENCY:  Environmental Protection                      I. General Information
                                           13, 2018, EPA published a direct final                  Agency (EPA).
                                           rule approving the updated delegation                   ACTION: Final rule.                                    A. Does this action apply to me?
                                           of authority for implementation and                                                                               You may be potentially affected by
                                           enforcement of NSPS and NESHAPs for                     SUMMARY:   This regulation establishes an              this action if you are an agricultural
                                           all sources (both part 70 and non-part 70               exemption from the requirement of a                    producer, food manufacturer, or
                                           sources) to the NMED. The direct final                  tolerance for residues of poly(oxy-1,2-                pesticide manufacturer. The following
                                           rule was published without prior                        ethanediyl), a-(1-oxoalkyl)-w-methoxy-,                list of North American Industrial
                                           proposal because EPA anticipated no                     where the alkyl chain contains a                       Classification System (NAICS) codes is
                                           relevant adverse comments. EPA stated                   minimum of 6 and a maximum of 18                       not intended to be exhaustive, but rather
                                           in the direct final rule that if relevant               carbons and the oxyethylene content is                 provides a guide to help readers
                                           adverse comments were received by                       3–13 moles, when used as an inert                      determine whether this document
                                           May 14, 2018, EPA would publish a                       ingredient (stabilizer and solubilizing                applies to them. Potentially affected
                                           timely withdrawal in the Federal                        agent) in pesticide formulations applied               entities may include:
                                           Register. EPA received an adverse                       to growing crops or raw agricultural                      • Crop production (NAICS code 111).
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                                           comment on May 14, 2018. Accordingly,                   commodities after harvest at a                            • Animal production (NAICS code
                                           EPA is withdrawing the direct final rule.               concentration not to exceed 25% by                     112).
                                           In a separate subsequent final action                   weight in the formulation. This related                   • Food manufacturing (NAICS code
                                           EPA will address the comment received.                  group of compounds are collectively                    311).
                                           The withdrawal is being taken pursuant                  known as the ethoxylated fatty acid                       • Pesticide manufacturing (NAICS
                                           to sections 111 and112 of the CAA.                      methyl esters (EFAMEs). BASF                           code 32532).


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Document Created: 2018-11-02 11:47:25
Document Modified: 2018-11-02 11:47:25
CategoryRegulatory Information
CollectionFederal Register
sudoc ClassAE 2.7:
GS 4.107:
AE 2.106:
PublisherOffice of the Federal Register, National Archives and Records Administration
SectionRules and Regulations
ActionFinal rule.
DatesThis rule is effective on July 5, 2018.
ContactLeiran Biton, Air Permits, Toxics, and Indoor Programs Unit, U.S. Environmental Protection Agency, EPA New England Regional Office, 5 Post Office Square--Suite 100, (Mail code OEP05-2), Boston, MA 02109-3912, tel. (617) 918-1267, email [email protected]
FR Citation83 FR 25922 
CFR AssociatedEnvironmental Protection; Air Pollution Control; Incorporation by Reference; Intergovernmental Relations; Reporting and Recordkeeping Requirements and Sulfur Oxides

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