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<title>Federal Register, Volume 91 Issue 1 (Friday, January 2, 2026)</title>
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[Federal Register Volume 91, Number 1 (Friday, January 2, 2026)]
[Rules and Regulations]
[Pages 43-52]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-24207]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R05-OAR-2024-0215; FRL-12351-02-R5]
Air Plan Approval; Michigan and Minnesota; Revision to Taconite
Federal Implementation Plan
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: The Environmental Protection Agency (EPA) is finalizing
nitrogen oxide (NO<INF>X</INF>) and/or sulfur dioxide (SO<INF>2</INF>)
limits for the indurating furnaces at five taconite facilities in
accordance with the procedures set forth in the Federal Implementation
Plan (FIP) addressing the requirement for best available retrofit
technology (BART) at taconite facilities. EPA is also modifying the
Upper Predictive Limit (UPL) equations used to establish NO<INF>X</INF>
and SO<INF>2</INF> emission limits under the FIP. Finally, the EPA is
revising reporting provisions to require reports be submitted to the
EPA electronically. The EPA is finalizing these actions pursuant to
Clean Air Act (CAA) sections 110 and 169A.
DATES: This final rule is effective on February 2, 2026.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-R05-OAR-2024-0215. All documents in the docket are
listed on the <a href="https://www.regulations.gov">https://www.regulations.gov</a> website. Although listed in
the index, some information is not publicly available, i.e.,
Confidential Business Information (CBI), Proprietary Business
Information (PBI), or other information the disclosure of which 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 either through <a href="https://www.regulations.gov">https://www.regulations.gov</a> or at the EPA,
Region 5, Air and Radiation Division, 77 West Jackson Boulevard,
Chicago,
[[Page 44]]
Illinois 60604. This facility is open from 8:30 a.m. to 4:30 p.m.,
Monday through Friday, excluding Federal holidays. The EPA recommends
that you telephone Kathleen D'Agostino, at (312) 886-1767 before
visiting the Region 5 office.
FOR FURTHER INFORMATION CONTACT: For information about this final rule,
contact Kathleen D'Agostino, Air and Radiation Division (AR18J),
Environmental Protection Agency, Region 5, 77 West Jackson Boulevard,
Chicago, Illinois 60604; telephone number (312) 886-1767; email address
<a href="/cdn-cgi/l/email-protection#c7a3a6a0a8b4b3aea9a8e9aca6b3afaba2a2a987a2b7a6e9a0a8b1"><span class="__cf_email__" data-cfemail="c1a5a0a6aeb2b5a8afaeefaaa0b5a9ada4a4af81a4b1a0efa6aeb7">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Preamble acronyms and abbreviations.
Throughout this preamble the use of ``we,'' ``us,'' or ``our'' is
intended to refer to the EPA. We use multiple acronyms and terms in
this preamble. While this list may not be exhaustive, to ease the
reading of this preamble and for reference purposes, the EPA defines
the following terms and acronyms here:
BART best available retrofit technology
CAA Clean Air Act
CBI Confidential Business Information
CEMS continuous emissions monitoring system
``Cliffs'' Cleveland-Cliffs, Inc., formerly known as Cliffs Natural
Resources
``Cliffs facilities'' Tilden, Hibbing, Minorca, Northshore, and
United Taconite
``Conservation Groups'' the National Parks Conservation Association,
Coalition to Protect America's National Parks, Minnesota Center for
Environmental Advocacy, and Sierra Club, collectively
EPA Environmental Protection Agency
FIP Federal Implementation Plan
``Hibbing'' Hibbing Taconite Company
``Minorca'' Minorca Mine
NESHAPs National Emission Standards for Hazardous Air Pollutants
``Northshore'' Northshore Mining Company--Silver Bay
NO<INF>X</INF> nitrogen oxide
NSPS New Source Performance Standards
``Original 2013 FIP'' FIP promulgated on February 6, 2013 (78 FR
8706)
PBI Proprietary Business Information
PRA Paperwork Reduction Act
RFA Regulatory Flexibility Act
RHR Regional Haze Rule rule promulgated on July 1, 1999 (64 FR
35714), codified at 40 CFR part 51, subpart P.
SO<INF>2</INF> sulfur dioxide
``Tilden'' Tilden Mining Company
UMRA Unfunded Mandates Reform Act
UPL Upper Predictive Limit
``U.S. Steel'' United States Steel
UTAC United Taconite
Organization of this document. The information presented in this
preamble is organized as follows:
I. Background
II. Public Comments
III. What action is the EPA taking?
IV. Statutory and Executive Order Reviews
I. Background
On February 6, 2013 (78 FR 8706), the EPA promulgated a FIP that
included BART limits for certain taconite furnaces in Minnesota and
Michigan (the ``Original 2013 FIP''). On April 16, 2016 (81 FR 21672),
in response to petitions for reconsideration and due to new information
submitted to the EPA after promulgation of the Original 2013 FIP, the
EPA revised the Original 2013 FIP (the ``2016 Revised FIP''). The 2016
Revised FIP revised emission limits for certain facilities and
established a process to confirm or modify those emission limits using
continuous emissions monitoring system (CEMS) data that were to be
collected after the installation of the selected low-NO<INF>X</INF>
technology. Under the 2016 Revised FIP, NO<INF>X</INF> emission limits
do not become enforceable until the EPA confirms or modifies the
emission limits in accordance with set procedures.
On December 4, 2024 (89 FR 96152), the EPA proposed to modify the
UPL equations used to establish NO<INF>X</INF> and SO<INF>2</INF>
emission limits and to finalize NO<INF>X</INF> and/or SO<INF>2</INF>
limits for the indurating furnaces at five taconite facilities in
accordance with the procedures set forth in the Original 2013 FIP and
2016 Revised FIP (the ``2024 Proposed Rule''). These facilities include
Tilden Mining Company (``Tilden''), located at 101 Cci Mine Road,
Ishpeming, Michigan; Hibbing Taconite Company (``Hibbing''), located at
4950 Highway 5 North, Hibbing, Minnesota; Minorca Mine (``Minorca''),
located at 5950 Old Highway 53, Virginia, Minnesota; Northshore Mining
Company--Silver Bay (``Northshore''), located at 10 Outer Drive, Silver
Bay, Minnesota, and United Taconite (``UTAC''), located at 8470
Townline Road, Forbes, Minnesota. Tilden, Minorca, Northshore, and UTAC
are owned by Cleveland-Cliffs, Inc. (``Cliffs''), formerly known as
Cliffs Natural Resources, and Hibbing is jointly owned by Cliffs and
United States Steel (``U.S. Steel''). The primary units identified as
being subject to BART at Tilden, Hibbing, Minorca, UTAC, and Northshore
include the following pelletizing (indurating) furnaces: Tilden Grate
Kiln Line 1, Hibbing Straight-Grate Lines 1-3, Minorca Straight-Grate
Line 1, UTAC Grate Kiln Lines 1 and 2, and Northshore Straight-Grate
Furnaces 11 and 12.\1\
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\1\ Fuel sulfur content BART limits were also set for two
process boilers and a line dryer at Tilden. Those limits are not
impacted by this action.
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Specifically, the EPA proposed to establish the following
NO<INF>X</INF> limits, with compliance to be determined on a rolling
30-day average: 3.0 pounds (lbs) NO<INF>X</INF> per million British
Thermal Unit (MMBtu) for all fuels for Tilden Line 1; a crossline
average limit of 1.5 lb NO<INF>X</INF>/MMBtu for Hibbing Lines 1, 2,
and 3; a crossline average emission limit of 3.0 lbs NO<INF>X</INF>/
MMBtu for all fuels for UTAC Lines 1 and 2; and 1.6 lbs NO<INF>X</INF>/
MMBtu for Minorca's indurating furnace. The EPA proposed to establish
the following SO<INF>2</INF> limits, with compliance to be determined
on a rolling 30-day average: 189 pounds of SO<INF>2</INF> per hour
(lbs/hr) for all fuels for Tilden Line 1; an aggregate emission limit
of 247.8 lbs SO<INF>2</INF>/hr for Hibbing Lines 1, 2, and 3; 68.2 lbs
SO<INF>2</INF>/hr for Minorca's indurating furnace; and an aggregate
limit of 17.0 lbs SO<INF>2</INF>/hr for Northshore Furnaces 11 and 12.
The EPA also proposed to revise the reporting requirements to require
reports be submitted to the EPA electronically. An explanation of the
CAA requirements, a detailed analysis of how these requirements apply
to the taconite facilities, and the EPA's reasons for proposing the
modified equations and revised limits were provided in the notice of
proposed rulemaking and will not be restated here.
II. Public Comments
The EPA held a virtual public hearing on December 9, 2024. The EPA
received no verbal or written comments at the virtual public hearing.
The comment period on the proposed action described above closed on
January 21, 2025. The EPA received one comment letter from the National
Parks Conservation Association, Coalition to Protect America's National
Parks, Minnesota Center for Environmental Advocacy, and Sierra Club
(collectively, the ``Conservation Groups''). The Conservation Groups'
comments are summarized and addressed below.
1. Comment: The Conservation Groups stated that Minnesota's six
taconite mining facilities and the one in Michigan are significant
sources of haze-forming pollution; however, the EPA proposed to approve
the facilities' data without conducting the BART analyses required
under the CAA and Regional Haze Rule (RHR).\2\ The Conservation Groups
alleged that the EPA improperly focuses only on the CEMS data provided
by the facilities. As a result, the Conservation Groups claim that the
EPA's proposed FIP Revision is arbitrary and capricious, in violation
of the CAA and the RHR.
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\2\ The RHR was published in the Federal Register July 1, 1999
(64 FR 35714), codified at 40 CFR part 51, subpart P.
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Response: The EPA disagrees that the Agency proposed emission
limits for
[[Page 45]]
Tilden, Hibbing, Minorca, Northshore, and United Taconite (the ``Cliffs
facilities'') without conducting the required BART analysis for each
facility. Under the RHR, each State (or in the case of a FIP, the EPA),
is directed to conduct BART determinations for such ``BART-eligible''
sources that may reasonably be anticipated to cause or contribute to
any visibility impairment in a Class I area.\3\ On July 6, 2005, 70 FR
39104, the EPA published the Guidelines for BART Determinations Under
the RHR at appendix Y to 40 CFR part 51 (the ``BART Guidelines'') to
assist States and the EPA in determining which sources should be
subject to the BART requirements and in determining appropriate
emission limits for each source subject to BART. The BART Guidelines
are mandatory for power plants above 750 megawatts and are considered
useful guidance for other types of sources. 70 FR 39104, 39108 (July 6,
2005).
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\3\ ``BART-eligible sources'' are those sources that have the
potential to emit 250 tons or more of a visibility-impairing air
pollutant, were not in operation prior to August 7, 1962, were in
existence on August 7, 1977, and whose operations fall within one or
more of 26 specifically listed source categories. 40 CFR 51.301.
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In the August 15, 2012, (77 FR 49312-49313) Proposed FIP, the EPA
conducted five-step BART analyses for the Cliffs facilities. The five-
step analyses were conducted in accordance with the BART Guidelines. In
the October 22, 2015, (80 FR 64160, 64166) Proposed FIP Revision, the
EPA revised the five-step BART analyses for the Cliffs facilities in
response to new information provided by the companies. In a final
action on April 12, 2016 (81 FR 21672), (the ``2016 Revised FIP''), the
EPA determined that low-stoich, low-NO<INF>X</INF> burners (LNBs) (for
grate kilns) and LNBs that utilize a combination of water, steam
injection, and pre-combustion technologies (for straight-grate kilns)
are the appropriate NO<INF>X</INF> reduction technology and constitute
BART for these taconite furnaces. Because these technologies had not
previously been used on taconite furnaces, the EPA set NO<INF>X</INF>
emission limits and set forth a process to confirm or modify those
emission limits using CEMS data that were to be collected after the
installation of the selected low-NO<INF>X</INF> technology. Under the
2016 Revised FIP, the NO<INF>X</INF> emission limits do not become
enforceable until the EPA confirms or modifies the emission limits in
accordance with procedures set forth in the 2016 Revised FIP.\4\ In the
current action, the EPA is modifying the BART emission limits in
accordance with the procedures set forth in the 2016 Revised FIP.
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\4\ See e.g., 40 CFR 52.1235(b)(1)(ii)(1).
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Similarly, in the Original 2013 FIP, the EPA determined that
existing controls reflected SO<INF>2</INF> BART for Hibbing, Minorca,
and Northshore and established SO<INF>2</INF> emission limits for each
furnace, with the option or requirement, depending on the facility,
that the owner or operator submit one year of CEMS data to the EPA to
set a revised SO<INF>2</INF> emission limit calculated using the
appropriate UPL equation.\5\ The 2016 Revised FIP restricted the sulfur
content of the coal burned at Tilden, set an SO<INF>2</INF> emission
limit, and required Tilden to submit one year of CEMS data to the EPA
to set a revised SO<INF>2</INF> emission limit calculated using the
appropriate UPL equation.\6\ In this action, the EPA is revising
SO<INF>2</INF> emission limits in accordance with the process set forth
in the Original 2013 FIP and 2016 Revised FIP. Therefore, as
demonstrated in the cited prior rulemakings, the EPA conducted the
required BART analyses prior to revising the NO<INF>X</INF> and
SO<INF>2</INF> emission limits in this action.
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\5\ See 40 CFR 52.1235 (b)(2)(ii),(v), and (vi).
\6\ See 40 CFR 52.1183(k)(3).
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2. Comment: The Conservation Groups assert that it is unreasonable
for the EPA to propose to relax the emission limits for NO<INF>X</INF>
and SO<INF>2</INF> from furnaces at the taconite mining facilities in
Michigan and Minnesota.
Response: The EPA disagrees that the emission limits in this action
are unreasonable. The RHR requires States (or in the case of a FIP, the
EPA) to develop an implementation plan that sets emission limits based
on the degree of reduction achievable through the application of the
best system of continuous emission reduction.\7\ As discussed in the
EPA's response to Comment 1, with respect to NO<INF>X</INF>, the EPA
conducted five-factor BART analyses in the Original 2013 FIP and
revised those BART analyses in the 2016 Revised FIP. Because the
technologies identified in the BART analyses had not previously been
used on taconite furnaces, the EPA set NO<INF>X</INF> emission limits
and established a process to either confirm or modify those emission
limits within established ranges using CEMS data that were to be
collected after the installation of the selected low-NO<INF>X</INF>
technology. The 2016 Revised FIP also allowed facilities to request for
EPA approval a single NO<INF>X</INF> limit for all fuels.\8\ The EPA is
not modifying the NO<INF>X</INF> BART determinations in the 2016
Revised FIP. Rather, in accordance with both the 2016 Revised FIP and
general BART requirements, the EPA is finalizing limits for these
facilities that reflect the degree of reduction achievable utilizing
the control technology identified in the 2016 Revised FIP BART
determinations, consistent with the process set forth in the 2016
Revised FIP.
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\7\ See 40 CFR 51.301 ``Best Available Retrofit Technology
(BART).''
\8\ The 2016 Revised FIP allowed each respective facility to
seek single NO<INF>X</INF> limits for Tilden at 40 CFR
52.1183(k)(1)(viii), and for UTAC at 40 CFR 52.1235(b)(1)(iv)(A)(8),
and 40 CFR 52.1235(b)(1)(iv)(B)(8).
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As discussed in the EPA's response to Comment 1, with respect to
SO<INF>2</INF>, the Agency conducted five-factor BART analyses in the
Original 2013 FIP and 2016 Revised FIP in which the Agency identified
BART controls, established SO<INF>2</INF> emission limits, and provided
a process for modifying those limits after the collection of CEMS
data.\9\ In this action, the EPA is not attempting to modify those BART
determinations; rather, the Agency is modifying SO<INF>2</INF> emission
limits for these facilities to reflect the degree of reduction
achievable utilizing the BART controls identified in accordance with
the process set forth in the Original 2013 FIP and 2016 Revised FIP.
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\9\ The 2016 Revised FIP allowed each respective facility to
seek single NO<INF>X</INF> limits for Tilden at 40 CFR
52.1183(k)(1)(viii), and for UTAC at 40 CFR 52.1235(b)(1)(iv)(A)(8),
and 40 CFR 52.1235(b)(1)(iv)(B)(8).
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3. Comment: The Conservation Groups assert that, although U.S.
Steel's Keetac mine emission limits appear in a second settlement
agreement, the EPA's proposal does not mention this information and
does not propose to revise the Keetac mine emission limits in the
proposed rulemaking.
Response: This action addresses NO<INF>X</INF> and SO<INF>2</INF>
emission limits only for the indurating furnaces at the Cliffs taconite
pellet production facilities, not the mines. The EPA proposed a
separate rule for the Keetac facility on April 24, 2025, at 90 FR
17233.
4. Comment: The Conservation Groups assert that the EPA's proposal
references the facilities' CEMS data, through which the taconite mining
facilities claim they are unable to meet the EPA's BART emission
limits. The Conservation Groups further assert that even if the CAA or
RHR could be interpreted to allow implementation of BART via such a
short-circuited approach, the EPA cannot rely on only the CEMS data to
ensure reasonable progress.
Response: The EPA disagrees with Conservation Groups' contention
that the EPA relied on CEMS data to ensure reasonable progress. In this
action, the EPA is finalizing NO<INF>X</INF> BART emission
[[Page 46]]
limitations for indurating furnaces at Tilden, Hibbing, UTAC, and
Minorca and SO<INF>2</INF> BART emission limits for indurating furnaces
at Tilden, Hibbing, Minorca, and Northshore in accordance with the
procedures set forth in the Original 2013 FIP and 2016 Revised FIP. The
EPA is not promulgating long-term strategies or establishing reasonable
progress goals for Minnesota or Michigan. Both States submitted, and
the EPA approved, regional haze State Implementation Plans (SIPs) for
the first planning period.
As discussed in the EPA's responses to Comments 1 and 2, the Agency
followed the BART process set forth in the RHR at 40 CFR part 51,
subpart P and the BART Guidelines. As explained in other responses
above, the EPA's five-factor SO<INF>2</INF> BART analyses for Hibbing,
Minorca, and Northshore were set forth in the proposed Original 2013
FIP and the Agency's five-factor NO<INF>X</INF> BART analyses for
Tilden, Hibbing, UTAC, and Minorca and SO<INF>2</INF> BART analysis for
Tilden were set forth in the proposed 2016 Revised FIP. The EPA's
NO<INF>X</INF> and SO<INF>2</INF> BART determinations were finalized in
the Original 2013 FIP and 2016 Revised FIP. See response to Comment 1.
On June 12, 2012 (77 FR 34801), the EPA approved Minnesota's
regional haze plan for the first implementation planning period as
satisfying the applicable requirements in 40 CFR 51.308 except for BART
emission limits for the taconite facilities. Among the regional haze
plan elements approved were Minnesota's long-term strategy for making
reasonable progress toward visibility goals. Minnesota's long-term
strategy did not rely on the achievement of any particular degree of
emission control from the taconite plants to achieve reasonable
progress goals. Rather, Minnesota evaluated emission controls from
other industrial sectors and facilities in the area to achieve progress
goals.
On December 3, 2012 (77 FR 71533), the EPA approved Michigan's
regional haze plan for the first implementation planning period as
satisfying the applicable requirements in 40 CFR 51.308 except for BART
emission limits for Tilden, St. Mary's Cement, and Escanaba Paper
Company. Among the regional haze plan elements approved was Michigan's
long-term strategy for making reasonable progress toward visibility
goals. Michigan's long-term strategy did not rely on the achievement of
any particular degree of emission control from the taconite plants to
achieve reasonable progress goals. The EPA is currently reconsidering
the RHR and may make changes to this determination after the
rulemaking, if appropriate.
5. Comment: The Conservation Groups assert that the EPA did not
propose to require that the taconite sources optimize their emission
control systems even though the EPA's Original 2013 FIP determined that
the taconite sources should be able to meet control efficiencies
substantially greater than seen in the CEMS reports. The Conservation
Groups assert that the EPA has repeatedly found that optimization of
emission controls is highly cost effective and thus the EPA must
require that the taconite sources optimize the emission control systems
and ensure that the FIP emission limits reflect the best system of
continuous emission reduction achievable.
Response: The EPA disagrees that the Original 2013 FIP or the 2016
Revised FIP required that an affected source ``optimize''
NO<INF>X</INF> reduction technology. The 2016 Revised FIP required
facilities to submit an engineering report and modeling of the
NO<INF>X</INF> reduction control technology being installed, including
process and control technology variables that impact NO<INF>X</INF>
emissions control technology performance and how these variables can be
adjusted to reduce NO<INF>X</INF> emissions. The limit confirmation and
modification process set forth in the 2016 Revised FIP further
specifies that only CEMS data that meet both pellet quality
specifications and proper furnace burner operation parameters be used
when calculating the final emission limit and may exclude data
resulting from operations inconsistent with the reported design
parameters of the NO<INF>X</INF> reduction control technology
installed. When calculating the emission limits, the EPA only used data
resulting from operations consistent with the design parameters of the
NO<INF>X</INF> reduction control technology specified in each
respective engineering report.
6. Comment: The Conservation Groups assert that the EPA lacks
authority to set an alternative BART average emission limit at Hibbing
Lines 1, 2 and 3 that is less stringent than controlling BART at each
of the individual units. According to the Conservation Groups, the EPA
calculated the individual BART emission limits for the three Hibbing
Lines as follows: 1.5 lbs NO<INF>X</INF>/MMBtu for Line 1; 1.4 lbs
NO<INF>X</INF>/MMBtu for Line 2; and 1.5 lbs NO<INF>X</INF>/MMBtu for
Line 3. The EPA's BART Guidelines allow a source ``to `average'
emissions across any set of BART-eligible emission units within a
fenceline, so long as the emission reductions from each pollutant being
controlled for BART would be equal to those reductions that would be
obtained by simply controlling each of the BART-eligible units that
constitute [a] BART-eligible source.'' The EPA's 2024 Proposed Rule
explains that the Agency averaged the single line limits described
above and calculated a crossline 720-hour average emission limit of 1.5
lbs NO<INF>X</INF>/MMBtu. However, the Conservation Groups assert that
the result of an average of those three values (1.4, 1.5 and 1.5) is
1.46. Thus, the Conservation Groups assert that the EPA must not use a
value of 1.5 because that would not be equal to reductions controlled
at Line 2.
Response: The EPA disagrees with the Conservation Groups' assertion
that the Agency does not have the authority to set alternative average
emission limits as calculated. As the Conservation Groups point out,
the BART Guidelines allow ``sources to `average' emissions across any
set of BART-eligible emission units within a fenceline, so long as the
emission reductions from each pollutant being controlled for BART would
be equal to those reductions that would be obtained by simply
controlling each of the BART-eligible units that constitute [a] BART-
eligible source.'' Hibbing operates three identical furnaces (Line 1,
Line 2, and Line 3) and installed the same burner design on each
furnace. Therefore, emission reductions are equal to the reductions
that would be obtained by controlling each BART-eligible unit. The
difference in individual NO<INF>X</INF> limits is due to variations in
CEMS data across the three units during the data collection period.\10\
EPA regulations such as New Source Performance Standards (NSPS) and
National Emission Standards for Hazardous Air Pollutants (NESHAPs)
generally establish emissions limits at two significant figures. In
addition, the BART Guidelines contain presumptive NO<INF>X</INF> and
SO<INF>2</INF> emissions limits for certain types of utility boilers,
all set at two significant figures. For Hibbing, the EPA averaged
emissions across the three lines and calculated a crossline average
emission limit of 1.5 lbs NO<INF>X</INF>/MMBtu. While the average of
1.5, 1.4, and 1.5 is 1.46 lbs NO<INF>X</INF>/MMBtu, all NO<INF>X</INF>
emission limits for the taconite furnaces have been set at two
significant figures and 1.46 rounds to 1.5.
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\10\ See Hibbing Emission Limit Calculations, available in the
docket for this action.
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7. Comment: The Conservation Groups assert that the EPA did not
include full BART analyses for the taconite sources. The Conservation
Groups further assert that the EPA did not evaluate the BART factors
here to
[[Page 47]]
ensure that the proposed emission limitation revisions satisfy those
factors.
Response: The EPA disagrees with this comment. See response to
Comment 1.
8. Comment: To conduct compliant BART analyses for the taconite
sources subject to BART, the Conservation Groups assert that the EPA
should have considered the available control train that the
Conservation Groups discuss in their 2024 Minnesota Comments, which
likely would result in lower emissions limits than included in the 2016
Revised FIP.\11\ The Conservation Groups assert that the EPA has never
codified that BART is determined at one time. To the extent that the
EPA believes that the Agency's prior BART determinations for the
taconite sources still serve as valid BART determinations when revised
by new data, the Conservation Groups assert that the EPA did not
articulate any such rationale. CAA section 169A(b)(2) makes clear that
BART is a mandatory part of ``each applicable implementation plan'' and
expressly requires that States (or, in the case of a FIP, the
Administrator) ``includ[e]'' BART for ``each'' eligible source.
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\11\ See Docket EPA-R05-OAR-2022-0974.
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Response: The EPA disagrees that this action requires new BART
analyses. As the Conservation Groups note, CAA section 169A(b)(2)(A)
requires ``each applicable implementation plan'' to include
requirements to install and operate BART. While the CAA does not define
the applicable implementation plans, the RHR does. Under the RHR at 40
CFR 51.308(d), ``States were required to submit SIPs addressing
regional haze visibility impairment in 2007, which covered what we
refer to as the first implementation period (2008-2018).'' 82 FR 3078,
3082 (January 10, 2017) (the ``2017 RHR''). For subsequent
implementation periods, ``[e]ach State identified in Sec. 51.300(b)
must revise and submit its regional haze implementation plan revision
to EPA by July 31, 2021, July 31, 2028, and every 10 years
thereafter.'' 40 CFR 51.308(f).
In the 2017 RHR, the EPA noted ``States were required to undertake
the BART determination process during the first implementation period.
The BART requirement was a one-time requirement. . . '' 82 FR 3078,
3083 (January 10, 2017).\12\ Therefore, while CAA section 169A(b)(2)(A)
requires ``each applicable implementation plan'' to include
requirements to go through the BART determination process, the RHR
establishes the various implementation plans under 40 CFR 51.308(b) and
(f) and only requires undergoing the BART determination process in the
first implementation plan under 40 CFR 51.308(e). Regardless, the EPA
agrees that BART was an explicit first implementation period
requirement and, as part of the first implementation period, the EPA's
BART determinations were finalized in the Original 2013 FIP and 2016
Revised FIP. Therefore, there is no requirement to re-evaluate BART
controls for the taconite sources. However, under the 2016 Revised FIP,
the NO<INF>X</INF> emission limits do not become enforceable until the
EPA confirms or modifies the emission limits in accordance with
procedures set forth in the 2016 Revised FIP. Therefore, in the current
action, the EPA is modifying the BART emission limits in accordance
with the BART determinations and procedures set forth in the Original
2013 FIP and 2016 Revised FIP. See response to Comment 1.
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\12\ See also, August 2019 Guidance on Regional Haze State
Implementation Plans for the Second Implementation Period, at A-3,
<a href="https://www.epa.gov/sites/default/files/2019-08/documents/8-20-2019_-_regional_haze_guidance_final_guidance.pdf">https://www.epa.gov/sites/default/files/2019-08/documents/8-20-2019_-_regional_haze_guidance_final_guidance.pdf</a>. ``BART. As a one-
time requirement during the first implementation period, 40 CFR
51.308(e) directed states to evaluate potential BART controls at
certain larger, often uncontrolled, older stationary sources in
order to address visibility impacts from these sources. States were
required to conduct five-factor BART determinations for 'BART-
eligible' sources that are anticipated to cause or contribute to any
visibility impairment in a Class I area. As an alternative to
requiring source-specific BART controls, states have the flexibility
to adopt an emissions trading program or other alternative program
as long as the alternative provides greater reasonable progress
towards improving visibility than BART and meets certain other
requirements set out in 40 CFR 51.308(e)(2).''
---------------------------------------------------------------------------
9. Comment: The Conservation Groups assert that nothing in the CAA
or RHR supports exempting the taconite sources from BART analyses based
on litigation and settlement negotiations. The Conservation Groups
contend that it is inappropriate for the EPA to rely on settlement
discussions between the EPA and the taconite facilities to avoid
meeting the CAA and RHR requirements for these facilities. Sierra Club
submitted comments on the proposed consent decree, to which the
Conservation Groups assert that the EPA has not yet responded.
Response: The EPA disagrees that the Agency is relying on the
settlement agreement to meet statutory obligations and disagrees that
the Agency is exempting the sources from BART analyses. As explained in
other responses above, the EPA's SO<INF>2</INF> BART analyses for
Hibbing, Minorca, and Northshore were set forth in the proposed
Original 2013 FIP and the EPA's NO<INF>X</INF> BART analyses for
Tilden, Hibbing, UTAC, and Minorca and SO<INF>2</INF> BART analysis for
Tilden were set forth in the proposed 2016 Revised FIP. The EPA's BART
determinations were finalized in the Original 2013 FIP and 2016 Revised
FIP. The EPA entered into a settlement agreement with Cliffs on
September 12, 2024, which detailed the results of the EPA's emission
limit calculations that were performed using CEMS data in accordance
with the procedures set forth in the Original 2013 FIP and 2016 Revised
FIP.\13\ While BART-eligible sources may be reassessed and subject to
additional control technologies in future implementation periods,
States (or the EPA when issuing a FIP) are not obligated to reopen
their BART determinations to consider additional data or control
technologies after the determination has been made. See also response
to Comment 1.
---------------------------------------------------------------------------
\13\ Settlement Agreement between Cleveland-Cliffs, Inc.,
Cleveland-Cliffs Steel, LLC, and U.S. EPA, Sep. 12, 2024.
---------------------------------------------------------------------------
Regarding Sierra Club's comments on the proposed settlement
agreement, under CAA section 113(g) the EPA is not obligated to respond
to comments on settlement agreements, only to consider such comments:
``The Administrator or the Attorney General, as appropriate, shall
promptly consider any such written comments and may withdraw or
withhold his consent to the proposed order or agreement if the comments
disclose facts or considerations which indicate that such consent is
inappropriate, improper, inadequate, or inconsistent with the
requirements of this chapter.'' \14\ The EPA considered Sierra Club's
comments and concluded it was appropriate to finalize the settlement.
---------------------------------------------------------------------------
\14\ See 42 U.S.C. 7413(g).
---------------------------------------------------------------------------
10. Comment: The Conservation Groups assert that the EPA withholds
emission data from the public, thwarting meaningful public
participation. The Conservation Groups further assert that Federal law
requires that hourly CEMS emissions data submitted by UTAC must be made
available to the public because the data is necessary to determine the
amount of emissions emitted by the source. Furthermore, the
Conservation Groups assert that the EPA does not provide enough
descriptive information about the ``process information'' that UTAC
also claimed as CBI to determine whether it is entitled to confidential
treatment. Therefore, the Conservation Groups assert that the EPA must
also conduct a CBI determination of those claims and fully describe the
Agency's analysis for the public because the Agency's disclosures are
necessary for
[[Page 48]]
the public to meaningfully review and comment on the proposed emission
limitations for the UTAC source.
Response: The EPA disagrees that that the Agency withheld UTAC
emission data from the public. The EPA provided all hourly emission
data submitted by UTAC covering the periods from December 12, 2018, to
February 24, 2019, and from January 25, 2022, to March 26, 2023,
including NO<INF>X</INF> emission data in lbs/MMBtu and NO<INF>X</INF>
emissions in lbs/MMBtu over a 720-hour average. The EPA also provided
the Agency's calculation file that details the Agency's analysis of
UTAC's emission data. These files are available in the docket for this
action.\15\ UTAC claimed as CBI the specific hourly fuel mix and the
percent stoich. The data claimed as CBI are not necessary to
``determine the amount of emissions emitted by the source'' and the EPA
is obligated to treat this information as confidential in accordance
with the procedures set forth in 40 CFR part 2, subpart B.
---------------------------------------------------------------------------
\15\ See Attachment to April, 11, 2023, email from McWilliams--
UTAC L1 L2 NOX CEMS data-filtering out values outside of engineering
specifications.pdf, Attachment to April 11, 2023, email from
McWilliams--UTAC L1 L2 NOX CEMS Raw Data 1-25-22 to 3-26-23.pdf,
Attachment to April, 11, 2023, email from McWilliams--UTAC Line 1
co-fire NOX data 2-12-18 to 2-25-19.pdf, Attachment to April, 11,
2023, email from McWilliams--UTAC Line 2 co-fire NOX data 11-14-22
to 3-5-23.pdf, and United Taconite Emission Limit Calculations.xlsx,
available in the docket.
---------------------------------------------------------------------------
11. Comment: The Conservation Groups assert that the EPA's
rationale for the relaxation of the emission limits and failure to
require additional measures by the taconite sources, failure to conduct
new BART analyses, and reliance on the flawed and outdated prior BART
analyses are not reasonably moored to the requirements of the CAA.
Rather than reducing pollution, the Conservation Groups assert that the
proposed changes will allow the taconite facilities to emit more haze-
forming pollution in the future.
Response: The EPA disagrees that this action is inconsistent with
the requirements of the CAA. As discussed in the response to Comment 8,
BART is a one-time requirement of the first planning period, per the
CAA. The EPA's BART analyses were set forth in the proposed Original
2013 FIP and proposed 2016 Revised FIP. The EPA's BART determinations
were finalized in the Original 2013 FIP and 2016 Revised FIP. See
response to Comment 1. The emission limits set forth in the 2024
Proposed Rule reflect the degree of reduction achievable utilizing the
control technology identified in the Original 2013 FIP and the 2016
Revised FIP BART determinations and are being set in conformance with
the processes set forth in both the Original 2013 FIP and 2016 Revised
FIP.
12. Comment: The Conservation Groups assert that the 2024 Proposed
Rule fails to include the details necessary for practical
enforceability. Specifically, the Conservation Groups assert that the
EPA's 2024 Proposed Rule fails to explain how the proposed revised
regulations identified for inclusion in the FIP comply with the
monitoring, recordkeeping, and reporting requirements of the CAA and
provide adequate reporting for citizen enforcement.
Response: The EPA disagrees that the 2024 Proposed rule had
insufficient detail to ensure enforceability. The regional haze
regulations codified in the Minnesota SIP at 40 CFR 52.1235(c), (d),
and (e) and the Michigan SIP at 40 CFR 52.1183(l), (m), and (n) contain
applicable monitoring, recordkeeping, and reporting requirements,
including semiannual compliance reports and quarterly excess emission
reports, and require that affected facilities submit such data to the
EPA. These data are publicly available through the Freedom of
Information Act (FOIA) process.
13. Comment: The Conservation Groups assert that CAA section
110(a)(2)(F)(iii), 42 U.S.C. 7410(a)(2)(F)(iii), and 40 CFR 51.211(a)
require FIPs to provide for periodic reporting ``on the nature and
amount of emissions'' from stationary sources. The Conservation Groups
further assert that the EPA's proposal and associated regulations do
not explain how the EPA will make the reported compliance information
available to the public and that the EPA's final FIP action must
provide this information.
Response: The EPA agrees that the reported compliance information
should be available to the public. The Air Emissions Reporting Rule
(AERR) at 40 CFR part 52 subpart A requires States to inventory
emission sources, including stationary sources, and report this
information to the EPA. The EPA makes these data publicly accessible on
the Agency's website at <a href="http://www.epa.gov/air-emissions-inventories">www.epa.gov/air-emissions-inventories</a>, which
hosts the National Emissions Inventory and provides information on the
AERR program. In addition, as stated in the response to Comment 12, the
regional haze regulations codified in the Minnesota SIP at 40 CFR
52.1235(e) and the Michigan SIP at 40 CFR 52.1183(n) contain applicable
reporting requirements, including semiannual compliance reports and
quarterly excess emission reports, and require that affected facilities
submit such data to the EPA. These data are publicly available through
the FOIA process.
14. Comment: The Conservation Groups assert that under the FIP,
certain future compliance plans and alternative monitoring procedures
would be developed outside of the EPA's FIP public notice and comment
process and the public will not have an opportunity to review and
comment via the FIP rulemaking process. The Conservation Groups further
assert that the EPA must revise the Agency's proposed regulations to
provide for public notice and comment on the plans and alternative
monitoring procedures.
The Conservation Groups assert that several provisions in the EPA's
proposed FIP regulations allow for the development of future plans and
alternative approaches to compliance:
<bullet> Sampling and calculation methodology for determining the
sulfur content of coal are determined via a plan, which is not part of
the FIP (Tilden Grate Kiln Line 1 (40 CFR 52.1183(k)(3)).
<bullet> Data substitution and CEMS supplementation calculated via
a site-specific monitoring plan, which is not part of the FIP (40 CFR
51.1183(l)(4)(xii)).
<bullet> Provisions that allow for the ``owner or operator'' to
``submit to EPA for approval an alternative monitoring procedure
request'' (40 CFR 52.1235(b)(2)(vi)(D)).
Response: The Conservation Groups state that the EPA must provide
for public notice and comment on ``future compliance plans and
alternative monitoring procedures.'' This appears to reference the
site-specific monitoring procedures promulgated in the Original 2013
FIP, codified at 40 CFR 52.1183(n)(8) and 52.1235(e)(8). These
provisions set forth the requirement that sources ``submit for review
and approval by the Regional Administrator a site-specific monitoring
plan'' and specify the minimum information to be included at 40 CFR
52.1183(n)(8)(i) through (x) and 52.1235(e)(8)(i) through (x). During
the public comment period for the Original 2013 FIP, the EPA took
comment on the procedures and provisions of the site-specific
monitoring plans. In this action, the EPA is not revising the
procedures set forth in the Original 2013 FIP for sources to submit to
the EPA for review and approval site-specific monitoring plans. This
action clarifies when certain information required to be in the site-
specific monitoring plans may be used to supplement CEMS data during
periods of startup, shutdown, and malfunction (SSM) or to develop an
alternative monitoring procedure under
[[Page 49]]
certain conditions. Therefore, comments on the procedures set forth in
the Original 2013 FIP are outside the scope of this action.
15. Comment: The Conservation Groups assert that the proposed
regulatory text omits monitoring requirements for Process Boilers #1
and #2 at Northshore. The Conservation Groups further assert that the
EPA must require CEMS to be installed on these units and apply the same
maintenance, reporting, and recordkeeping requirements to them as are
applied to the other CEMS because those provisions are necessary to
ensure the emission limits at the process boilers--which apply during
periods of SSM--are enforceable.
Response: The EPA disagrees that regulatory text regarding
monitoring requirements for Process Boiler #1 and #2 are necessary for
this action. The provisions related to these boilers were promulgated
in the Original 2013 FIP and are not being revised by this action,
except to reflect the compliance date of October 10, 2021. The EPA
solicited comment on the Original 2013 FIP and new comments on these
provisions are outside the scope of this action.
16. Comment: The Conservation Groups assert that, contrary to the
CAA's requirement that emission limits apply at all times, the EPA's
proposed FIP regulations do not specify this requirement for all of the
taconite sources. The Conservation Groups further assert that the only
taconite source with such a provision is Northshore (40 CFR.
52.1235(b)(vi)). Therefore, the Conservation Groups assert that the
EPA's final regulations must specify that the emission limits apply at
all times for all units, including SSM periods.
Response: The EPA disagrees with the Conservation Groups' assertion
that the FIP should be modified to specify that emission limits apply
at all times. The FIP already clearly requires that the emission limits
apply at all times and this action does not impact that provision. The
Original 2013 FIP, codified at 40 CFR 52.1235(e)(7)(x)(A) and 40 CFR
52.1183(n)(7)(x)(A), clearly states ``[f]or purposes of this section,
an excess emission is defined as any 30-day or 720-hour rolling average
period, including periods of startup, shutdown, and malfunction,
[emphasis added], during which the 30-day or 720-hour (as appropriate)
rolling average emissions of either regulated pollutant (SO<INF>2</INF>
and NO<INF>X</INF>), as measured by a CEMS, exceeds the applicable
emission standards in this section.''
III. What action is the EPA taking?
The EPA is modifying the UPL equations used to establish
NO<INF>X</INF> and SO<INF>2</INF> emission limits and finalizing
NO<INF>X</INF> and/or SO<INF>2</INF> emission limits for the indurating
furnaces at five taconite facilities in accordance with the procedure
set forth in the Original 2013 FIP and 2016 Revised FIP. Specifically,
the EPA is establishing the following NO<INF>X</INF> limits, with
compliance to be determined on a rolling 30-day average: 3.0 lbs
NO<INF>X</INF>/MMBtu for all fuels for Tilden Line 1; a crossline
average limit of 1.5 lb NO<INF>X</INF>/MMBtu for Hibbing Lines 1, 2,
and 3; a crossline average emission limit of 3.0 lbs NO<INF>X</INF>/
MMBtu for all fuels for UTAC Lines 1 and 2; and 1.6 lbs NO<INF>X</INF>/
MMBtu for Minorca's indurating furnace. The EPA is establishing the
following SO<INF>2</INF> limits, with compliance to be determined on a
rolling 30-day average: 189 lbs SO<INF>2</INF>/hr for all fuels for
Tilden Line 1; an aggregate emission limit of 247.8 lbs SO<INF>2</INF>/
hr for Hibbing Lines 1, 2, and 3; 68.2 lbs SO<INF>2</INF>/hr for
Minorca's indurating furnace; and an aggregate limit of 17.0 lbs
SO<INF>2</INF>/hr for Northshore Furnaces 11 and 12. The EPA is also
revising reporting provisions to require reports to be submitted to the
Agency electronically. The EPA is currently reconsidering the RHR and
may make changes to this determination after the rulemaking, if
appropriate.
IV. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review 13563
This action is exempt from review by the Office of Management and
Budget (OMB) because it is a rule of particular applicability and will
only apply to five taconite facilities--Tilden in Michigan and Hibbing,
Minorca, Northshore, and UTAC in Minnesota.
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is not subject to Executive Order 14192 because actions
that are rules of particular applicability are exempt from review under
Executive Order 12866. This action will specifically regulate five
taconite facilities--Tilden in Michigan and Hibbing, Minorca,
Northshore. and UTAC in Minnesota.
C. Paperwork Reduction Act (PRA)
This rule does not impose an information collection burden under
the provisions of the PRA.
D. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA (5
U.S.C. 601 et seq.). This action will not impose any requirements on
small entities. This action will establish emission limits for five
taconite sources. None of these sources are owned by small entities and
therefore are not small entities.
E. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any State,
local, or Tribal governments or the private sector.
F. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This rule does not have Tribal implications as specified in
Executive Order 13175. It will not have substantial direct effects on
Tribal governments. Thus, Executive Order 13175 does not apply to this
rule. However, the EPA did discuss this action in conference calls with
the Michigan and Minnesota Tribes.
H. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
This action is not subject to Executive Order 13045 because it is
not 3(f)(1) significant as defined in Executive Order 12866.
I. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use
This action is not subject to Executive Order 13211 because it is
not a significant regulatory action under Executive Order 12866.
J. National Technology Transfer Advancement Act
This rulemaking does not involve technical standards.
K. Congressional Review Act
This rule is exempt from the Congressional Review Act because it is
[[Page 50]]
a rule of particular applicability. This action will specifically
regulate five taconite facilities--Tilden in Michigan and Hibbing,
Minorca, Northshore, and UTAC in Minnesota.
L. Judicial Review
Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by March 3, 2026. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this rule for the purposes of judicial review or 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, Nitrogen oxides, Regional haze,
Reporting and recordkeeping requirements, and Sulfur oxides.
Lee Zeldin,
Administrator.
For the reasons stated in the preamble, title 40 CFR part 52 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.
0
2. Section 52.1183 is amended by:
0
a. Revising paragraphs (k)(1), (3), (4) and (5);
0
b. Revising paragraphs (l)(3), (4)(v) and (xii);
0
c. Revising paragraphs (n)(1) and (2) introductory text; and
0
d. Removing and reserving paragraph (p).
The revisions read as follows:
Sec. 52.1183 Visibility protection.
* * * * *
(k) Tilden Mining Company, or any subsequent owner/operator of the
Tilden Mining Company facility in Ishpeming, Michigan, shall meet the
following requirements:
(1) NO<INF>X</INF> Emission Limits. (i) An emission limit of 3.0
lbs NO<INF>X</INF>/MMBTU, based on a 30-day rolling average, shall
apply to Tilden Grate Kiln Line 1 (EUKILN1) beginning February 2, 2026.
(ii) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X.</INF>
* * * * *
(3) The owner or operator of the Tilden Grate Kiln Line 1 (EUKILN1)
furnace shall meet an emission limit of 189.0 lbs SO<INF>2</INF>/hr,
based on a 30-day rolling average, beginning on February 2, 2026.
Compliance with this emission limit shall be demonstrated with data
collected by a continuous emissions monitoring system (CEMS) for
SO<INF>2</INF>. Beginning November 12, 2016, any coal burned on Tilden
Grate Kiln Line 1 shall have no more than 0.60 percent sulfur by weight
based on a monthly block average. The sampling and calculation
methodology for determining the sulfur content of coal must be
described in the monitoring plan required for this furnace.
(4) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in (k)(5)
must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#6634532734223403160914120f08012603160748010910"><span class="__cf_email__" data-cfemail="9ccea9ddced8cef9ecf3eee8f5f2fbdcf9ecfdb2fbf3ea">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
(5) Records shall be kept for any day during which fuel oil is
burned as fuel (either alone or blended with other fuels) in Grate Kiln
Line 1. These records must include, at a minimum, the gallons of fuel
oil burned per hour, the sulfur content of the fuel oil, and the
SO<INF>2</INF> emissions in pounds per hour. If any fuel oil is burned
after the first day that SO<INF>2</INF> CEMS are required to be
operational, then the records must be submitted, for each calendar
year, to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#1143245043554374617e6365787f76517461703f767e67"><span class="__cf_email__" data-cfemail="3e6c0b7f6c7a6c5b4e514c4a5750597e5b4e5f10595148">[email protected]</span></a> no later
than 30 days after the end of each calendar year.
(l) * * *
(3) The owner or operator shall install, certify, calibrate,
maintain, and operate one or more continuous diluent monitor(s)
(O<INF>2</INF> or CO<INF>2</INF>) and continuous stack gas flow rate
monitor(s) on Tilden Grate Kiln Line 1 to allow conversion of the
NO<INF>X</INF> and SO<INF>2</INF> concentrations to units of the
standard (lbs/MMBTU and lbs/hr, respectively) unless a demonstration is
made that a diluent monitor and/or continuous flow rate monitor are not
needed for the owner or operator to demonstrate compliance with
applicable emission limits in units of the standard.
(4) * * *
(v) The owner or operator of each CEMS must furnish the Regional
Administrator a written report of the results of each quarterly
performance evaluation and a data accuracy assessment pursuant to 40
CFR part 60 appendix F within 60 days after the calendar quarter in
which the performance evaluation was completed. These reports shall be
submitted to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#4d1f780c243f08232b223f2e28202823390d283d2c632a223b"><span class="__cf_email__" data-cfemail="a6f493e7cfd4e3c8c0c9d4c5c3cbc3c8d2e6c3d6c788c1c9d0">[email protected]</span></a>.
* * * * *
(xii) Data substitution must not be used for purposes of
determining compliance under this regulation. If CEMS data is measuring
only a portion of the NO<INF>X</INF> or SO<INF>2</INF> emitted during
startup, shutdown, or malfunction conditions, the CEMS data may be
supplemented, but not modified, by the addition of calculated emission
rates using procedures set forth in the site specific monitoring plan.
* * * * *
(n) Reporting requirements. (1) Unless instructed otherwise, all
requests, reports, submittals, notifications, and other communications
required by this section shall be submitted to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#fdafc8bc948fb8939b928f9e9890989389bd988d9cd39a928b"><span class="__cf_email__" data-cfemail="f5a7c0b49c87b09b939a87969098909b81b5908594db929a83">[email protected]</span></a>. References in this section
to the Regional Administrator shall mean the EPA Regional Administrator
for Region 5.
(2) The owner or operator of each BART affected unit identified in
this section and CEMS required by this section must provide to the
Regional Administrator the written notifications, reports, and plans
identified at paragraphs (n)(2)(i) through (viii) of this section.
* * * * *
(p) [Reserved]
0
3. Section 52.1235 is amended by:
0
a. Revising paragraphs (b)(1)(ii), (iv), (v), (vi), (2)(ii), (v) and
(vi);
0
b. Revising paragraphs (c)(1), (2), (3), (4)(ii), (v), and (xii); and
0
c. Revising paragraphs (e)(1) and (2) introductory text; and
0
d. Revising paragraph (f).
The revisions read as follows:
Sec. 52.1235 Regional haze.
* * * * *
(b) * * *
(1) * * *
(ii) Hibbing Taconite Company--(A) An aggregate emission limit of
1.5 lbs NO<INF>X</INF>/MMBtu, based on a 30-day rolling average, shall
apply to the combined NO<INF>X</INF> emissions from the three
indurating furnaces, Line 1 (EU020), Line 2 (EU021), and Line 3
(EU022), beginning on February 2, 2026. To determine the aggregate
emission rate,
[[Page 51]]
the combined NO<INF>X</INF> emissions from Lines 1, 2, and 3 shall be
divided by the total heat input to the three lines (in MMBtu) during
every rolling 30-day period.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
* * * * *
(iv) United Taconite--(A) An aggregate emission limit of 3.0 lbs
NO<INF>X</INF>/MMBtu, based on a 30-day rolling average, shall apply to
the combined NO<INF>X</INF> emissions from the two indurating furnaces,
Grate Kiln Line 1 (EU040) and Grate Kiln Line 2 (EU042), beginning on
February 2, 2026. To determine the aggregate emission rate, the
combined NO<INF>X</INF> emissions from Grate Kiln Line 1 and Grate Kiln
Line 2 shall be divided by the total heat input to the two lines (in
MMBtu) during every rolling 30-day period.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
(v) Minorca Mine--(A) An emission limit of 1.6 lbs NO<INF>X</INF>/
MMBtu, based on a 30-day rolling average, shall apply to the Minorca
Mine indurating furnace (EU026). This emission limit will become
enforceable on February 2, 2026.
(B) Compliance with this emission limit will be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
NO<INF>X</INF>.
(vi) Northshore Mining Company--Silver Bay: An emission limit of
1.5 lbs NO<INF>X</INF>/MMBtu, based on a 30-day rolling average, shall
apply to Furnace 11 (EU100/EU104) beginning October 10, 2018. An
emission limit of 1.5 lbs NO<INF>X</INF>/MMBtu, based on a 30-day
rolling average, shall apply to Furnace 12 (EU110/114) beginning
October 11, 2019. However, for any 30, or more, consecutive days when
only natural gas is used at either Northshore Mining Furnace 11 or
Furnace 12, a limit of 1.2 lbs NO<INF>X</INF>/MMBtu, based on a 30-day
rolling average, shall apply. An emission limit of 0.085 lbs
NO<INF>X</INF>/MMBtu, based on a 30-day rolling average, shall apply to
Process Boiler #1 (EU003) and Process Boiler #2 (EU004) beginning
October 10, 2021. The 0.085 lbs NO<INF>X</INF>/MMBtu emission limit for
each process boiler applies at all times a unit is operating, including
periods of start-up, shut-down and malfunction.
(2) * * *
(ii) Hibbing Taconite Company--(A) An aggregate emission limit of
247.8 lbs SO<INF>2</INF>/hour, based on a 30-day rolling average, shall
apply to the combined SO<INF>2</INF> emissions from the three
indurating furnaces, Line 1 (EU020), Line 2 (EU0021), and Line 3
(EU022), beginning on February 10, 2017. To determine the aggregate
emission rate, the combined SO<INF>2</INF> emissions from Lines 1, 2,
and 3 shall be divided by the total hours of operation of the three
lines during every rolling 30-day period.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
SO<INF>2</INF>.
(C) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in
(b)(2)(vii) must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#fcaec9bdaeb8ae998c938e8895929bbc998c9dd29b938a"><span class="__cf_email__" data-cfemail="7426413526302611041b06001d1a13341104155a131b02">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
* * * * *
(v) Minorca Mine--(A) An emission limit of 68.2 lbs SO<INF>2</INF>/
hr, based on a 30-day rolling average, shall apply to the indurating
furnace (EU026) beginning February 2, 2026.
(B) Compliance with this emission limit shall be demonstrated with
data collected by a continuous emissions monitoring system (CEMS) for
SO<INF>2</INF>.
(C) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in
(b)(2)(vii) must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#3361067261776156435c41475a5d54735643521d545c45"><span class="__cf_email__" data-cfemail="3466017566706651445b46405d5a53745144551a535b42">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
(vi) Northshore Mining Company--Silver Bay--(A) An aggregate
emission limit of 17.0 lbs SO<INF>2</INF>/hr, based on a 30-day rolling
average, shall apply to Furnace 11 (EU100/EU104) and Furnace 12 (EU110/
EU114) beginning February 2, 2026. To determine the aggregate emission
rate, the combined SO<INF>2</INF> emissions from Furnace 11 and Furnace
12 shall be divided by the total hours of operation of the two furnaces
during every rolling 30-day period.
(B) Compliance with these emission limits shall be demonstrated
with data collected by a continuous emissions monitoring system (CEMS)
for SO<INF>2</INF>.
(C) Emissions resulting from the combustion of fuel oil are not
included in the calculation of the 30-day rolling average. However, if
any fuel oil is burned after the first day that SO<INF>2</INF> CEMS are
required to be operational, then the information specified in
(b)(2)(vii) must be submitted, for each calendar year, to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#8cdeb9cddec8dee9fce3fef8e5e2ebcce9fceda2ebe3fa"><span class="__cf_email__" data-cfemail="6634532734223403160914120f08012603160748010910">[email protected]</span></a> no later than 30 days after the
end of each calendar year so that a limit can be set.
(D) The owner or operator may submit to EPA for approval an
alternative monitoring procedure request. The request shall include at
least one year of CEMS data demonstrating consistent values at or below
5 lbs SO<INF>2</INF>/hr. The alternative monitoring procedure request
shall not remove the obligation to maintain and operate a flow rate
monitor in the stack. If approved, the owner or operator would not be
required to operate the SO<INF>2</INF> CEMS and may demonstrate
continuous compliance using an emission factor derived from the average
of at least one year of existing SO<INF>2</INF> data using the
procedure set forth in the site specific monitoring plan, and verified
by annual stack tests using EPA approved test methods, multiplied by
the daily measured flow rate as recorded by the flow rate monitor and
recorded as the daily lb/hr SO<INF>2</INF> emission rate.
* * * * *
(c) Testing and monitoring. (1) The owner or operator of the
respective facility shall install, certify, calibrate, maintain and
operate continuous emissions monitoring systems (CEMS) for
NO<INF>X</INF> on United States Steel Corporation, Keetac unit EU030;
Hibbing Taconite Company units EU020, EU021, and EU022; United States
Steel Corporation, Minntac units EU225, EU261, EU282, EU315, and EU334;
United Taconite units EU040 and EU042; Minorca Mine unit EU026; and
Northshore Mining Company-Silver Bay units Furnace 11 (EU100/EU104) and
Furnace 12 (EU110/EU114). Compliance with the emission limits for
NO<INF>X</INF> shall be determined using data from the CEMS.
(2) The owner or operator shall install, certify, calibrate,
maintain, and operate CEMS for SO<INF>2</INF> on United States Steel
Corporation, Keetac unit EU030; Hibbing Taconite Company units EU020,
EU021, and EU022; United States Steel Corporation, Minntac units EU225,
EU261, EU282, EU315, and EU334; United Taconite units EU040 and EU042;
Minorca Mine unit EU026; and Northshore Mining Company-Silver Bay units
Furnace 11 (EU100/EU104) and Furnace 12 (EU110/EU114).
(3) The owner or operator shall install, certify, calibrate,
maintain, and operate one or more continuous diluent monitor(s)
(O<INF>2</INF> or CO<INF>2</INF>) and continuous stack gas flow rate
monitor(s) on the
[[Page 52]]
BART affected units to allow conversion of the NO<INF>X</INF> and
SO<INF>2</INF> concentrations to units of the standard (lbs/MMBTU and
lbs/hr, respectively) unless a demonstration is made that a diluent
monitor and/or continuous flow rate monitor are not needed for the
owner or operator to demonstrate compliance with applicable emission
limits in units of the standards.
(4) * * *
(ii) CEMS must be installed and operational such that the
operational status of the CEMS identified in paragraphs (c)(1) and (2)
of this section shall be verified by, as a minimum, completion of the
manufacturer's written requirements or recommendations for
installation, operation, and calibration of the devices.
* * * * *
(v) The owner or operator of each CEMS must furnish the Regional
Administrator a written report of the results of each quarterly
performance evaluation and a data accuracy assessment pursuant to 40
CFR part 60 appendix F within 60 days after the calendar quarter in
which the performance evaluation was completed. These reports shall be
submitted to the Regional Administrator at <a href="/cdn-cgi/l/email-protection#227017634b50674c444d5041474f474c56624752430c454d54"><span class="__cf_email__" data-cfemail="144621557d66517a727b66777179717a60547164753a737b62">[email protected]</span></a>.
* * * * *
(xii) Data substitution must not be used for purposes of
determining compliance under this section. If CEMS data is measuring
only a portion of the NO<INF>X</INF> or SO<INF>2</INF> emitted during
startup, shutdown, or malfunction conditions, the CEMS data may be
supplemented, but not modified, by the addition of calculated emission
rates using procedures set forth in the site specific monitoring plan.
* * * * *
(e) Reporting Requirements. (1) Unless instructed otherwise, all
requests, reports, submittals, notifications, and other communications
required by this section shall be submitted to the Regional
Administrator at <a href="/cdn-cgi/l/email-protection#085a3d49617a4d666e677a6b6d656d667c486d7869266f677e"><span class="__cf_email__" data-cfemail="d587e094bca790bbb3baa7b6b0b8b0bba195b0a5b4fbb2baa3">[email protected]</span></a>. References in this section
to the Regional Administrator shall mean the EPA Regional Administrator
for Region 5.
(2) The owner or operator of each BART affected unit identified in
this section and CEMS required by this section must provide to the
Regional Administrator the written notifications, reports and plans
identified at paragraphs (e)(2)(i) through (viii) of this section.
* * * * *
(f) Equations for establishing the upper predictive limit--(1)
Equation for normal distribution and statistically independent data.
[GRAPHIC] [TIFF OMITTED] TR02JA26.003
Where:
x = average or mean of hourly test run data;
t<INF>[(</INF>n<INF>-1),(0.99)]</INF> = t score, the one-tailed t
value of the Student's t distribution for a specific degree of
freedom (n-1) and a confidence level (0.99, to reflect the 99th
percentile)
s<SUP>2</SUP> = variance of the hourly data set;
n = number of values (e.g., 5,760 if 8 months of valid lbs
NO<INF>X</INF>/MMBTU hourly values)
m = number of values used to calculate the test average (m = 720 as
per averaging time)
(i) To determine if statistically independent, use the Rank von
Neumann Test on p. 137 of data Quality Assessment: Statistical Methods
for Practitioners EPA QA/G-9S.
(ii) Alternative to Rank von Neumann test to determine if data are
dependent, data are dependent if t test value is greater than t
critical value, where:
[GRAPHIC] [TIFF OMITTED] TR02JA26.004
[rho] = correlation between data points
t critical = t<INF>[(n-2),(0.95)]</INF> = t score, the two-tailed t
value of the Student's t Distribution for a specific degree of
freedom (n-2) and a confidence level (0.95)
(iii) The Anderson-Darling normality test is used to establish
whether the data are normally distributed. That is, a distribution is
considered to be normally distributed when p > 0.05.
(2) Non-parametric equation for data not normally distributed and
normally distributed but not statistically independent.
m = (n+1) * [alpha]
m = the rank of the ordered data point, when data are sorted
smallest to largest. The data points are 720-hour averages for
establishing NO<INF>X</INF> limits.
n = number of data points (e.g., 5,040 720-hourly averages for eight
months of valid NO<INF>X</INF> lbs/MMBTU values)
[alpha] = 0.99, to reflect the 99th percentile
If m is a whole number, then the limit, UPL, shall be computed as:
UPL = Xm
Where:
X<INF>m</INF> = value of the mth data point in terms of lbs
SO<INF>2</INF>/hr or lbs NO<INF>X</INF>/MMBtu, when the data are
sorted smallest to largest.
If m is not a whole number, the limit shall be computed by linear
interpolation according to the following equation.
UPL = xm = xmi.md = xmi + 0.md(xm(i+1)<INF>-</INF>xmi)
Where:
mi = the integer portion of m, i.e., m truncated at zero decimal
places, and
md = the decimal portion of m
[FR Doc. 2025-24207 Filed 12-31-25; 8:45 am]
BILLING CODE 6560-50-P
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Document
Air Plan Approval; Michigan and Minnesota; Revision to Taconite Federal Implementation Plan
The Environmental Protection Agency (EPA) is finalizing nitrogen oxide (NO<INF>X</INF>) and/or sulfur dioxide (SO<INF>2</INF>) limits for the indurating furnaces at five taconit...
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91 FR 43
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“Air Plan Approval; Michigan and Minnesota; Revision to Taconite Federal Implementation Plan,” thefederalregister.org (January 2, 2026), https://thefederalregister.org/documents/2025-24207/air-plan-approval-michigan-and-minnesota-revision-to-taconite-federal-implementation-plan.