# Arizona.
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Final rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is taking final action to approve the State of Arizona's “SIP Revision: 2015 Ozone NAAQS, Yuma Redesignation Request and Maintenance Plan” (“Yuma Maintenance Plan” or “Plan”) as a revision to the Arizona state implementation plan (SIP). The Yuma Maintenance Plan includes, among other elements, an emissions inventory consistent with attainment, a maintenance demonstration, contingency provisions, and a motor vehicle emissions budget for use in transportation conformity determinations for the ten-year maintenance period. With this action, the EPA is approving the motor vehicle emissions budgets for 2020, 2030, and 2037. The EPA is also approving the State's request to redesignate the Yuma nonattainment area (“Yuma area”) from nonattainment to attainment for the 8-hour national ambient air quality standards (NAAQS) for ozone promulgated in 2015 (“2015 ozone NAAQS”). The EPA is finalizing this action because this SIP revision meets the applicable Clean Air Act (CAA or “Act”) requirements for maintenance plans and because the State has met the requirements under the Act for redesignation of a nonattainment area to attainment with respect to the Yuma area.
**DATES:**
This action is effective on December 18, 2025.
**ADDRESSES:**
The EPA has established a docket for this action under Docket ID No. EPA-R09-OAR-2024-0339. All documents in the docket are listed on the *https://www.regulations.gov* website. Although listed in the index, some information is not publicly available, *e.g.,* Confidential Business Information 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 through *https://www.regulations.gov,* or please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section for additional availability information. If you need assistance in a language other than English or if you are a person with a disability who needs a reasonable accommodation at no cost to you, please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section.
**FOR FURTHER INFORMATION CONTACT:**
Andrew Ledezma, EPA Region IX, 75 Hawthorne St., San Francisco, CA 94105. By phone: (415) 972-3985 or by email at *[email protected].*
**SUPPLEMENTARY INFORMATION:**
Throughout this document, “we,” “us,” and “our” refer to the EPA.
**Table of Contents**
I. Summary of Proposed Action
II. Public Comments and EPA Responses
III. Final Action
IV. Statutory and Executive Order Reviews
**I. Summary of Proposed Action**
On November 5, 2024, under CAA section 110(k)(3), the EPA proposed to approve the Yuma Maintenance Plan submitted by the Arizona Department of Environmental Quality (ADEQ) on December 27, 2023, as a revision to the Arizona SIP. [^1] In so doing, we proposed to find that the Yuma Maintenance Plan adequately demonstrates that the Yuma area will maintain the 2015 ozone NAAQS for ten years beyond redesignation and includes sufficient contingency provisions to promptly correct any violation of the 2015 ozone NAAQS that may occur, and otherwise meets the requirements for maintenance plans under CAA section 175A. We also proposed to find the motor vehicle emissions budgets (“budgets”) for volatile organic compounds (VOC) and nitrogen oxides (NO <sub>X</sub> ) for 2020, 2030, and 2037 adequate and approve the budgets for transportation conformity purposes.
[^1] 89 FR 87828 (November 5, 2024).
In our proposed rulemaking, we also proposed to grant ADEQ's request to redesignate the Yuma area from nonattainment to attainment for the 2015 ozone NAAQS pursuant to CAA section 107(d)(3)(E). We proposed to do so based on our conclusion that the Yuma area has attained the 2015 ozone NAAQS based on the following: the most recent three-year period (2020-2022) of quality-assured, certified, and complete ozone data; [^2] the relevant portions of the Arizona SIP are, or will be as part of this action, fully approved; the improvement in air quality is due to permanent and enforceable emissions reductions; Arizona has met all requirements applicable to the Yuma area with respect to section 110 and part D of the CAA; and based on our proposed approval as described above, the Yuma Maintenance Plan meets the requirements for maintenance plans under section 175A of the CAA. Therefore, Arizona has met the criteria for redesignation under CAA section 107(d)(3)(E) for the Yuma area with respect to the 2015 ozone NAAQS.
[^2] The Yuma 2015 ozone NAAQS design value for 2024 remained in attainment at 0.069 parts per million; EPA, 2024 AQS Design Value Report (AMP480) dated July 8, 2025, included in the docket for this rulemaking; also available at EPA, Ozone Design Values, 2024, *https://www.epa.gov/air-trends/air-quality-design-values.*
Our proposed rulemaking has a detailed discussion of the background for this action, our procedural and substantive review of the Yuma Maintenance Plan and associated budgets, and our rationale for our proposed approval of the Yuma Maintenance Plan and for granting ADEQ's request for redesignation of the Yuma area to attainment.
**II. Public Comments and EPA Responses**
Our November 5, 2024 (89 FR 87828) proposed rulemaking provided a 30-day public comment period that closed on December 5, 2024. During this comment period we received one comment, which stated that the cannabis industry is responsible for significant greenhouse gas and VOC emissions in Arizona. We acknowledge the comment; however, it fails to assert or explain how the EPA's approval of Arizona's redesignation request for the Yuma area and the Yuma Maintenance Plan is erroneous or otherwise inconsistent with the CAA, applicable regulations, or other authorities. As such, the comment does not require further response in order to finalize the action as proposed.
**III. Final Action**
Under CAA section 110(k)(3), and for reasons set forth in our November 5, 2024 (89 FR 87828) proposed rulemaking, the EPA is taking final action to approve the Yuma Maintenance Plan submittal as a revision to the Arizona SIP. The EPA finds that the maintenance demonstration showing the area will continue to maintain the 2015 ozone NAAQS for 10 years beyond redesignation, the contingency provisions describing the actions that ADEQ will take in the event of a future monitored violation, and the other elements of the Yuma Maintenance Plan meet all applicable requirements for maintenance plans and related contingency provisions in CAA section 175A. The EPA is also approving the budgets for VOC and NO <sub>X</sub> for 2020, 2030, and 2037 because they are derived from an approvable maintenance demonstration, are adequate, and meet the applicable transportation conformity requirements under 40 CFR 93.118(e).
Under CAA section 107(d)(3)(D), we are also taking final action to grant ADEQ's request to redesignate the Yuma area to attainment for the 2015 ozone NAAQS, which accompanied the submittal of the Yuma Maintenance Plan. We are doing so based on our conclusion that the area has met the five criteria for redesignation under CAA section 107(d)(3)(E). Our conclusion in this regard is based on our determination of the following: the area has attained the 2015 ozone NAAQS; relevant portions of the Arizona SIP are, or will be as part of this action, fully approved; the improvement in air quality is due to permanent and enforceable reductions in emissions; Arizona has met all requirements applicable to the Yuma area with respect to section 110 and part D of the CAA; and our approval (as part of this action) of the Yuma Maintenance Plan.
**IV. Statutory and Executive Order Reviews**
Under the Clean Air Act, redesignation of a nonattainment area to attainment and the accompanying approval of a maintenance plan under section 107(d)(3)(E) are actions that affect the status of a geographical area and do not impose any additional regulatory requirements on sources beyond those imposed by the SIP and applicable Federal rules. Redesignation to attainment does not in and of itself create any new requirements, but rather results in the applicability of less stringent requirements contained in the CAA for areas that have been redesignated to attainment. Moreover, 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, the EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. Accordingly, these actions merely approve a SIP revision and redesignation request as meeting Federal requirements and do not impose additional requirements beyond those imposed by State law. For these reasons, these actions:
• 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);
• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review 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 in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;
• 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
The EPA has identified Tribal areas within the Yuma area covered by this rule that would be potentially affected by this final action. Specifically, the Cocopah Tribe of Arizona and the Quechan Tribe of the Fort Yuma Indian Reservation are located within the boundaries of the Yuma area.
The EPA has concluded that this rule may have Tribal implications for these Tribes for the purposes of transportation conformity, as this document sets motor vehicle emissions budgets for ozone precursors for the Yuma area, which includes some Tribal roads. The EPA has communicated with the potentially affected Tribes located within the boundaries of the Yuma area. [^3]
[^3] Letter dated June 4, 2024, from Matthew Lakin, Director, EPA Region IX to Sherry Cordova, Chairwoman, Cocopah Tribe of Arizona, Subject: “Invitation to Consult on a Redesignation Request and Maintenance Plan from the State of Arizona for the 2015 Ozone National Ambient Air Quality Standards (NAAQS),” and letter dated June 4, 2024 from Matthew Lakin, Director, EPA Region IX to Jordan Joaquin, President, Quechan Tribe of the Fort Yuma Indian Reservation, Subject: “Invitation to Consult on a Redesignation Request and Maintenance Plan from the State of Arizona for the 2015 Ozone National Ambient Air Quality Standards (NAAQS).”
This action is subject to the Congressional Review Act, and the EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. 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 January 20, 2026. 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**
Environmental protection, Air pollution control, Incorporation by reference, Nitrogen dioxide, Particulate matter, Reporting and recordkeeping requirements, Sulfur dioxide, Volatile organic compounds.
Environmental protection, Air pollution control, National parks, Wilderness areas.
**Authority:**
42 U.S.C. 7401 *et seq.*
Dated: September 29, 2025.
Michael Martucci,
Acting Regional Administrator, Region IX.
For the reasons stated in the preamble, the EPA amends 40 CFR parts 52 and 81 as follows:
**PART 52—APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS**
**40 CFR Part 52**
1. The authority citation for part 52 continues to read as follows:
**Authority:**
42 U.S.C. 7401 *et seq.*
**Subpart D—Arizona**
**40 CFR Part 52**
2. Section 52.120 is amended in paragraph (e), table 1, under the heading “Part D Elements and Plans (Other than for the Metropolitan Phoenix or Tucson Areas)” by adding an entry for “SIP Revision: 2015 Ozone NAAQS, Yuma Redesignation Request and Maintenance Plan” before the entry for “SIP Revision: Marginal Ozone Plan for the Yuma Nonattainment Area (dated December 17, 2020), excluding chapter D and appendix C” to read as follows:
§ 52.120
(e) * * *
| Name of SIP provision | Applicable geographic or nonattainment area or title/subject | State submittal date | EPA approval date | Explanation |
| --- | --- | --- | --- | --- |
| | | | | |
| * * * * * * * | | | | |
| | | | | |
| SIP Revision: 2015 Ozone NAAQS, Yuma Redesignation Request and Maintenance Plan | Yuma 2015 8-hour ozone nonattainment area | December 27, 2023 | November 18, 2025, 90 FR [INSERT
PAGE WHERE THE DOCUMENT BEGINS] | Adopted by the Arizona Department of Environmental Quality on December 15, 2023, and submitted to the EPA as an attachment to a letter dated December 27, 2023. |
| | | | | |
| * * * * * * * | | | | |
**PART 81—DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES**
**40 CFR Part 81**
3. The authority citation for part 81 continues to read as follows:
**Authority:**
42 U.S.C. 7401, *et seq.*
**Subpart C—Section 107 Attainment Status Designations**
**40 CFR Part 81**
4. Section 81.303 is amended in the table “Arizona—2015 8-Hour Ozone NAAQS [Primary and Secondary]” by revising the entry for “Yuma, AZ” to read as follows:
§ 81.303
| Designated area | Designation | Date | Type | Classification | Date | Type |
| --- | --- | --- | --- | --- | --- | --- |
| | | | | | | |
| * * * * * * * | | | | | | |
| Yuma, AZ | December 18, 2025 | Attainment | | | | |
| Yuma County (part): | | | | | | |
| That portion within Yuma County of the area described by the following: | | | | | | |
| 1. Bounded on the north and west by the Arizona state line. | | | | | | |
| 2. Bounded on the south by the line of latitude at 32°39′20″ N. | | | | | | |
| 3. Bounded on the east by the line of longitude 114°33′50″ W. | | | | | | |
| 4. And excluding the sections 10, 11, and 12 of township T9S, R23W and any portion in Indian Country. | | | | | | |
| Cocopah Tribe of Arizona. | | | | | | |
| Quechan Tribe of the Fort Yuma Indian Reservation. | | | | | | |
| | | | | | | |
| * * * * * * * | | | | | | |