SUPPLEMENTARY INFORMATION:

Throughout this document, “we,” “us,” and “our” refer to the EPA. ( printed page 37367)

Table of Contents

I. Background

II. The State's Submittal

A. What did the State submit?

B. Are there other versions of these statutes and rules?

C. What is the purpose of the submitted statutes and rules?

III. The EPA's Evaluation and Action

A. How is the EPA evaluating the submittals?

B. Do the submittals meet the evaluation criteria?

C. EPA Recommendations to Further Improve the Rules

D. Public Comment and Proposed Action

IV. Incorporation by Reference

V. Statutory and Executive Order Reviews

I. Background

Under the CAA, the EPA has promulgated national ambient air quality standards (NAAQS) for certain pervasive air pollutants. The EPA has determined that attainment and maintenance of the NAAQS concentration levels is required to protect public health ( i.e., the “primary” NAAQS) and welfare ( i.e., the “secondary” NAAQS). Under the CAA, states are required to develop and submit SIPs to implement, maintain, and enforce the NAAQS. The EPA is responsible for designating areas of the country as “attainment,” “nonattainment,” or “unclassifiable” for the various NAAQS. States with nonattainment areas are required to submit revisions to their SIPs that include a control strategy necessary to demonstrate how the area will attain the NAAQS. The EPA assigns each nonattainment area a classification (“Moderate” or “Serious” for CO and particulate matter of ten microns or less (PM₁₀) nonattainment areas and “Marginal,” “Moderate,” “Serious,” “Severe,” or “Extreme” for ozone nonattainment areas), which determines the requirements that will apply to the area.

In 1978 the EPA designated Maricopa County and the Phoenix area portion of Pima County as nonattainment for the 1971 CO NAAQS.^[1] In 1986, the EPA disapproved the CO plan submitted by the ADEQ.^[2] In 1988, in response to a lawsuit and court order, the EPA proposed a federal implementation plan (FIP) that required the use of oxygenated gasoline during the winter months in the Phoenix area, among other CO control measures.^[3] Following the EPA's proposed FIP, ADEQ submitted additional measures to control CO in the Phoenix area, including an oxygenated gasoline requirement from September 30 through March 31 of each year, a trip reduction program applicable in portions of Pima County, and the GSA program. The EPA approved ADEQ's submittal into the SIP and withdrew its proposed FIP.^[4]

Under the CAA Amendments of 1990, the Phoenix area was classified as a Moderate nonattainment area for both ozone and PM₁₀ and a Marginal nonattainment area for CO. In 1996, the Phoenix area was reclassified as a Moderate nonattainment area for CO ^[5] and as a Serious nonattainment area for PM₁₀ .^[6] Additionally, the Phoenix area was classified as a Moderate nonattainment area for ozone ^[7] and later reclassified as a Serious nonattainment area for the 1-hour ozone standards.^[8]

CAA section 211(k) requires the use of “reformulated gasoline” (RFG) in nine geographic areas of the United States with the worst ozone pollution at the time of the 1990 CAA Amendments.^[9] RFG is gasoline that meets the requirements of 40 CFR 1090 to reduce emissions of ozone-forming pollutants. States with Marginal, Moderate, Serious, or Severe ozone nonattainment areas are permitted to opt in to the RFG program requirements by application to the EPA.^[10]

In 1997, the State of Arizona opted into the RFG program for the Phoenix area.^[11] Later that year, the State submitted a petition to opt out of the program to adopt a more stringent state fuels program, the CBG program. The EPA approved the State's interim CBG program as a revision to the Arizona SIP for the purpose of reducing both ozone and PM₁₀ in February 1998,^[12] and we approved the State's opt-out petition in August 1998.^[13]

Arizona later extended the CBG program requirements to a larger geographic area referred to as “Area A” ^[14] and made other revisions to enact the requirements as a permanent program. The EPA approved the State's revised, permanent CBG program in 2004.^[15] In addition to its use as a control measure for ozone and PM₁₀ , the permanent CBG program was also approved as a CO control measure.^[16]

In addition to the CBG program, Arizona adopted a Winter Oxygenated Fuel program in Tucson and adjacent areas in Pima County known as “Area B.” ^[17] The Winter Oxygenated Fuels program requires gasoline to contain a minimum oxygen content of 1.8 percent by weight from September 30 through March 31 of each year. This measure was enacted in connection with the approval of the 1996 CO limited maintenance plan for the Tucson Air Planning Area (as updated August 1997). The EPA approved this requirement into the SIP in 2000 ^[18] and as part of the area's CO maintenance plan in 2008.^[19]

II. The State's Submittal

A. What did the State submit?

The statutes and rules included in this SIP submittal include revisions to the State's CBG program and GSA program. These revisions were adopted by the Arizona State Legislature and the Weights and Measures Services Division (WMSD) of the Arizona Department of Agriculture and submitted by ADEQ to the EPA on June 17, 2021.^[20] Supplemental information was submitted in 2025.^[21] ADEQ is the governor's designee for submitting official revisions of the Arizona SIP to the EPA. Table 1 below identifies the ( printed page 37368) statutes and rules reviewed in this proposed rule for approval into and/or removal from the Arizona SIP, with the dates that they became effective locally and the dates that they were submitted by ADEQ.

CAA sections 110(a)(1), 110(a)(2), and 110(l) require a state to provide reasonable public notice and opportunity for public hearing prior to the adoption and submittal of a SIP or SIP revision. To meet this requirement, every SIP submittal should include evidence that adequate public notice was given and that a public hearing (if requested) was held consistent with the EPA's implementing regulations in 40 CFR 51.102.

Attachment A of the ADEQ submittal documents the public process followed by ADEQ in developing, adopting, and submitting this SIP revision. On May 8 and 9, 2021, ADEQ published a notice, in a newspaper of general circulation in ( printed page 37369) the Phoenix area, of a public hearing to be held on June 8, 2021, and the availability of the draft version for public review and comment. ADEQ conducted the public hearing on June 8, 2021, and received no comments on the draft SIP revision. ADEQ subsequently adopted and submitted the SIP revision to the EPA by a letter dated June 17, 2021. ADEQ has therefore satisfied the applicable statutory and regulatory procedural requirements for adoption and submittal of this SIP revision.

On December 17, 2021, the submittal for the statutes and rules submitted on June 17, 2021, was deemed by operation of law to meet the completeness criteria in 40 CFR part 51, Appendix V, which must be met before formal EPA review.

B. Are there other versions of these statutes and rules?

Most of the submitted statutes and rules will supersede or replace previously approved versions in the Arizona SIP. See Table 2 below for the statutes and rules that are superseded by approval of the statutes and rules covered in this action and the dates on which the previous versions were approved by the EPA. Table 2 also lists the GSA statutes that are being removed from the SIP without replacement, along with the dates that they were approved by the EPA. The CBG statutes and rules were renumbered in 2016 to reflect the transfer of the Arizona Department of Weights and Measures into the WMSD within the Arizona Department of Agriculture, and other rule provisions were revised for clarification or stylistic purposes. The Technical Support Document (TSD) for this action includes additional information regarding statutes and rules that are replaced by new provisions included in this submittal.

C. What is the purpose of the submitted statutes and rules?

The statutes and rules listed above establish Arizona's CBG program at the time ADEQ submitted this SIP revision. The submitted revisions reflect multiple updates to the program, including the following: updates to incorporate the most current standards adopted by ASTM International for gasoline; revisions to allow the use of isobutanol as a fuel additive; allowance of the use of the California Reformulated Gasoline Blendstocks for Oxygenate Blending (CARBOB) Model ^[22] as an alternative testing method; changes to Reid Vapor Pressure (RVP) standards outside of the summer ozone season; clarifications related to access to sampling records, quality assurance and quality controls for CBG suppliers, pipelines and third party terminals; limitations on the use of methyl tert-butyl ether (MTBE) as an oxygenate; new provisions allowing third party terminals to blend transmix; allowing recertification of CBG blendstock if an oxygenate blender uses an approved oxygenate that differs from the supplier's blending instructions; and updates to the materials incorporated by reference related to the California Predictive Model and the Federal Complex Model. The TSD contains additional information about these changes.

III. The EPA's Evaluation and Action

A. How is the EPA evaluating the submittals?

SIP rules must be enforceable (CAA section 110(a)(2)), must not interfere with applicable requirements concerning attainment and Reasonable Further Progress (RFP) or other CAA requirements (CAA section 110(l)), and must not modify certain SIP control requirements in nonattainment areas without ensuring equivalent or greater emissions reductions (CAA section 193). Additional CAA requirements apply to SIP revisions addressing state fuel programs. CAA section 211(c)(4)(A) preempts states from regulating motor fuel characteristics or components where the EPA has adopted a control or prohibition under section 211(c)(1),^[23] unless the state control is identical to the federal control. The EPA may waive preemption by approving the state requirements into a SIP. Approval of state fuel controls or prohibitions into a SIP requires the EPA to determine that the program is necessary to achieve NAAQS implemented by the SIP.^[24]

The Energy Policy Act of 2005 (EPAct) amended the CAA by requiring the EPA, in consultation with the Department of Energy (DOE), to determine the total number of fuels approved into all SIPs under section 211(c)(4)(C) as of September 1, 2004, and to publish a list identifying these fuels and the States and Petroleum Administration for Defense Districts (PADD) in which they are used.^[25] The EPAct also established three additional restrictions on the EPA's authority to waive preemption by approving a state fuel program into a SIP:

• First, the EPA may not approve a state fuel program into the SIP if it would cause an increase in the total number of fuel types approved into SIPs as of September 1, 2004.^[26]

• Second, the EPA is required to make a finding, after consultation with the DOE, that the new fuel will not cause supply or distribution interruptions or have a significant adverse impact on fuel producibility in the affected or contiguous areas.^[27]

• Third, with the exception of 7.0 psi RVP, the EPA may not approve a state fuel into a SIP unless that fuel type is already approved in at least one SIP in the applicable PADD. CAA Section 211(c)(4)(C)(v)(I), (IV), and (V).^[28]

On December 28, 2006, the EPA published our final interpretation of the EPAct provisions.^[29] We also determined and published a list of fuels approved into all SIPs under section 211(c)(4)(C) as of September 1, 2004. These state fuels are also known as “boutique fuels.” Arizona's CBG appears on the final list as two boutique fuels: a summer blend in effect from May 1 to September 30, and a non-summer blend in effect from October 1 to April 30.^[30]

Generally, SIP revisions to an approved state fuel program that are within the scope of a previous necessity finding do not require another “necessity” demonstration under CAA section 211(c)(4)(C)(i). In addition, revisions that do not result in a “new fuel type” within the meaning of CAA section 211(c)(4)(C) would not implicate the EPAct restrictions. Revisions that do not raise preemption issues under CAA 211(c)(4)(C) or are administrative in nature because they improve and strengthen an existing SIP-approved program by clarifying provisions and updating references do not result in changes to “required specific fuel components, specifications or limits,” and thus do not result in a “new fuel type.”

B. Do the submittals meet the evaluation criteria?

We have determined that the statutes and rules in the 2021 submittal and 2025 supplements are consistent with CAA requirements and relevant guidance regarding enforceability and SIP revisions. Additionally, the updates to the State's CBG program do not result ( printed page 37371) in a “new fuel” as prohibited under the EPAct.

CAA section 110(l) states that the EPA cannot approve a SIP revision if it would interfere with any applicable requirement concerning attainment, or RFP, or any other applicable CAA requirement. The revisions submitted by ADEQ are administrative in nature and will not result in increased emissions.

The TSD contains additional discussion of our evaluation, including our specific analyses of how the submitted statutes and rules meet the applicable requirements. Based on our review and evaluation of the 2021 submittal and 2025 supplements, as discussed in our TSD, we are proposing to determine that the statutes and rules submitted for inclusion in the Arizona SIP are consistent with CAA requirements and relevant guidance regarding enforceability and SIP revisions and would not interfere with RFP or attainment of any NAAQS or otherwise modify existing SIP requirements in a way that would reduce overall emissions reductions. Additionally, the State's elimination of the GSA program and updates to its CBG and winter oxygenated fuel programs regarding fuel characteristics and components are either not preempted or fall within the scope of our previous “necessity” finding as required by CAA section 211(c)(4)(C),^[31] and do not result in any “new fuel” as described in EPAct 2005. Consequently, we are proposing to approve the submitted revisions amending the CBG program and eliminating the GSA program into the Arizona SIP.

The CBG revisions we propose to approve are administrative in nature. They update the existing SIP-approved program by clarifying provisions, updating references, and enhancing program flexibility and our proposed action will not impose any additional costs or regulatory burdens. We therefore anticipate that our proposed action will have no impact upon the supply or price of gasoline in the Phoenix metropolitan area. Additionally, the requirements of the Arizona CBG program are currently subject to the EPA's waiver of federal enforcement of state boutique fuel requirements for gasoline.^[32]

C. EPA Recommendations to Further Improve the Rules

The TSD includes additional recommendations for the next time Arizona modifies the rules. This section of the TSD also describes changes made to the CBG program in 2023 that have revised the regulations relative to the submitted versions. As described in the TSD, our final approval of the current submittal into the SIP will make the submitted regulations federally enforceable regardless of any subsequent changes adopted by Arizona, and the State will be responsible for implementing the rules as approved by the EPA. Our recommendations include a general recommendation for the State to work with the EPA prior to making any further changes to the CBG program, to ensure that subsequent SIP submittals will meet applicable CAA requirements and will be approvable as revisions to the approved program.

D. Public Comment and Proposed Action

As authorized in section 110(k)(3) of the Act, the EPA proposes to fully approve the submitted rules because they fulfill all relevant requirements. We will accept comments from the public on this proposal until July 23, 2026. If we take final action to approve the submitted rules, our final action will incorporate these rules into the federally enforceable SIP.

IV. Incorporation by Reference

In this rule, the EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference the statutes and rules as identified and described in Section II of this preamble. The EPA has made, and will continue to make, these documents available through www.regulations.gov and at the EPA Region IX office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

V. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve State choices, provided that they meet the criteria of the CAA. 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 underExecutive Order 12866 (58 FR 51735, October 4, 1993);
• Is not anExecutive Order 14192 (90 FR 9065, February 6, 2025) regulatory action because this action is not significant under Executive Order 12866;
• 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 inExecutive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject toExecutive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;
• Is not a significant regulatory action subject toExecutive Order 13211 (66 FR 28355, May 22, 2001); and
• 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.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the 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).

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

91 FR 37366