# California.
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Final rule.
**SUMMARY:**
The Environmental Protection Agency (EPA) is taking final action to approve the “2023 Maintenance Plan and Redesignation Request for the Revoked 1-Hour Ozone Standard” (“San Joaquin Valley Maintenance Plan” or “Plan”) as a revision to the state implementation plan (SIP) for the State of California. The San Joaquin Valley Maintenance Plan includes, among other elements, an emissions inventory consistent with attainment and contingency provisions. The EPA is also finalizing its finding that the State of California's request to redesignate the San Joaquin Valley area from nonattainment to attainment for the revoked 1979 1-hour national ambient air quality standard (NAAQS or “standard”) for ozone (“1979 ozone NAAQS,” “1-hour ozone NAAQS,” or “1-hour ozone standard”) meets all the Clean Air Act (CAA or “the Act”) criteria for redesignation. Therefore, the EPA is terminating all anti-backsliding obligations for the San Joaquin Valley area for the revoked 1-hour ozone NAAQS.
**DATES:**
This action will be effective on October 27, 2025.
**ADDRESSES:**
The EPA has established a docket for this action under Docket ID No. EPA-R09-OAR-2024-0611. 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 June 23, 2025, under CAA section 110(k)(3), the EPA proposed to approve the San Joaquin Valley Maintenance Plan submitted by the California Air Resources Board (CARB) on July 21, 2023, as a revision to the California SIP. [^1] Consistent with the requirements in CAA section 175A and EPA guidance, [^2] we proposed to find that the San Joaquin Valley Maintenance Plan adequately addressed the required elements of a maintenance plan: an emissions inventory, a maintenance demonstration, a commitment to maintain an air quality monitoring network, verification of continued attainment, and a contingency plan.
[^1] 90 FR 26469 (June 23, 2025).
[^2] See memorandum dated September 4, 1992, from John Calcagni, Director, Air Quality Management Division, Office of Air Quality Planning and Standards, EPA, Subject: “Procedures for Processing Requests to Redesignate Areas to Attainment.”
In our proposed action, we also proposed to find that California's redesignation request meets all five criteria for redesignation in CAA section 107(d)(3)(E) for the 1-hour ozone NAAQS. We proposed to find that the San Joaquin Valley area meets the criteria in CAA section 107(d)(3)(E) based on the following: the San Joaquin Valley area attained the 1979 ozone NAAQS based on the 2021-2023 period of quality-assured, certified, and complete ozone data; the applicable portions of the California SIP are fully approved; the improvement in air quality is due to permanent and enforceable emissions reductions; California has met all requirements applicable to the San Joaquin Valley area with respect to section 110 and part D of the CAA; and based on our proposed approval as described above, the San Joaquin Valley Maintenance Plan meets the requirements for maintenance plans under section 175A of the CAA. Therefore, California has met the criteria for redesignation under CAA section 107(d)(3)(E) for the San Joaquin Valley area with respect to the 1979 ozone NAAQS.
Although CAA section 107(d)(3) applies explicitly only to revisions of area designations and the designations for this area have been revoked along with the NAAQS, the EPA's view is that, consistent with the U.S. Court of Appeals for the District of Columbia Circuit's findings in *South Coast Air Quality Management District* v. *EPA (* “ *South Coast II”)* , [^3] satisfaction of the statutory redesignation criteria permits the termination of any remaining anti-backsliding obligations for the San Joaquin Valley area as to the revoked 1979 ozone NAAQS. Therefore, we proposed to terminate anti-backsliding obligations, identified at 40 CFR 51.1100(o), for the San Joaquin Valley area associated with the 1-hour ozone NAAQS and to revise the table in 40 CFR part 81 to reflect the status of applicable anti-backsliding obligations in the San Joaquin Valley area for the revoked 1979 ozone NAAQS.
[^3] 882 F.3d 1138 (D.C. Cir. 2018).
Our proposed rulemaking has a detailed discussion of the background for this action, our procedural and substantive review of the San Joaquin Valley Maintenance Plan, and our rationale for terminating anti-backsliding obligations for the San Joaquin Valley area associated with the 1-hour ozone NAAQS.
**II. Public Comments and EPA Responses**
Our June 23, 2025 proposed rulemaking provided a 30-day public comment period that closed on July 22, 2025. During this period, we received comment letters from two organizations and one anonymous commenter. CARB and the San Joaquin Valley Unified Air Pollution Control District (“SJVUAPCD”) submitted letters supporting the EPA's proposed action. [^4] The anonymous commenter submitted a comment objecting to our proposed action. In the following paragraphs, we will summarize the comment objecting to our proposed action and provide our response.
[^4] Letter dated July 22, 2025, from Edie Chang, Deputy Executive Officer, CARB to Joshua F.W. Cook, Regional Administrator, EPA Region IX; and letter dated July 23, 2025, from Emily Kneeland, Director of Air Quality Planning, SJVUACPD.
The anonymous commenter states the EPA's regulations should be updated to address new sources of environmental issues, such as wildfires and changes in the ozone. The commenter states that this implementation plan should be revised to address outdated EPA standards and to ensure citizens are protected.
We acknowledge the comment; however, it fails to assert or explain how the EPA's approval of the San Joaquin Valley Maintenance Plan and finding that the redesignation request meets all criteria in CAA section 107(d)(3)(E) is erroneous or otherwise inconsistent with the CAA, applicable regulations, or other authorities. We also note that the San Joaquin Valley area remains in nonattainment for several more recent and more stringent ozone standards, which requires the development and implementation of state implementation plans to reduce ozone concentrations in the San Joaquin Valley area to levels the EPA has determined are protective of human health. 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 June 23, 2025 proposed rule, the EPA is taking final action to approve the San Joaquin Valley Maintenance Plan submittal as a revision to the California SIP. The EPA finds that the maintenance demonstration showing the area will continue to maintain the 1979 ozone NAAQS for 10 years beyond redesignation, the contingency provisions describing the actions that SJVUAPCD and CARB will take in the event of a future monitored violation, and the other elements of the San Joaquin Valley Maintenance Plan meet all applicable requirements for maintenance plans and related contingency provisions in CAA section 175A.
We are also determining that all five of the redesignation criteria at CAA section 107(d)(3)(E) for the San Joaquin Valley area have been met for the standard. We are terminating the anti-backsliding obligations for the San Joaquin Valley area with respect to the revoked 1-hour ozone NAAQS. Consistent with the *South Coast II* decision, anti-backsliding obligations for the revoked ozone standard may be terminated when the redesignation criteria for that standard are met.
**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. While we are not in this action redesignating any areas to attainment, we are approving the state's demonstration that all five redesignation criteria have been met. Similar to a redesignation, the termination of anti-backsliding obligations in this action does not impose any new requirements.
With regard to the SIP approval portions of this action, 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 CAA; and
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).
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 November 24, 2025. 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, Sulfur Dioxide, Reporting and recordkeeping requirements, Volatile organic compounds.
Environmental protection, Air pollution control, Carbon monoxide, Intergovernmental relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur oxides, Volatile organic compounds.
**Authority:**
42 U.S.C. 7401 *et seq.*
Dated: September 11, 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 F—California**
**40 CFR Part 52**
2. In § 52.220a, in paragraph (e), amend table 8 by adding an entry for “2023 Maintenance Plan and Redesignation Request for the Revoked 1-Hour Ozone Standard” after the entry for “Letter from David Warner, Deputy Air Pollution Control Officer, San Joaquin Valley Unified APCD, to Gerardo C. Rios, Chief, Air Permits Office, EPA Region IX, dated June 26, 2014.”
§ 52.220a
(e) * * *
| Name of SIP provision | Applicable geographic area | State submittal date | EPA approval date | Explanation |
| --- | --- | --- | --- | --- |
| | | | | |
| * * * * * * * | | | | |
| 2023 Maintenance Plan and Redesignation Request for the Revoked 1-Hour Ozone Standard | San Joaquin Valley | July 21, 2023 | 9/25/2025, 90 FR [INSERT
PAGE WHERE THE DOCUMENT BEGINS] | Submitted on July 21, 2023, as an attachment to a letter of the same date. |
| | | | | |
| * * * * * * * | | | | |
**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. In § 81.305 amend the table, “California—Ozone (1-Hour Standard),” by:
a. Revising the entry for “San Joaquin Valley Area”; and
b. Adding footnote “7”.
The revisions and additions read as follows:
§ 81.305
| Designated area | Designation | Date | Type | Classification | Date | Type |
| --- | --- | --- | --- | --- | --- | --- |
| | | | | | | |
| * * * * * * * | | | | | | |
| San Joaquin Valley Area: | | | | | | |
| Fresno County | 10/27/2025 | (
) | | | | |
| Kern County (part). That portion of Kern County that lies west and north of a line described below: | 10/27/2025 | (
) | | | | |
| Beginning at the Kern-Los Angeles County boundary and running north and east along the northwest boundary of the Rancho La Pliebre Land Grant to the point of intersection with the range line common to Range 16 West and Range 17 West, San Bernardino Base and Meridian; north along the range line to the point of intersection with the Rancho El Tejon Land Grant boundary; then southeast, northeast, and northwest along the boundary of the Rancho El Tejon Grant to the northwest corner of Section 3, Township 11 North, Range 17 West; then west 1.2 miles; then north to the Rancho El Tejon Land Grant boundary; then northwest along the Rancho El Tejon line to the southeast corner of Section 34, Township 32 South, Range 30 East, Mount Diablo Base and Meridian; then north to the northwest corner of Section 35, Township 31 South, Range 30 East; then northeast along the boundary of the Rancho El Tejon Land Grant to the southwest corner of Section 18, Township 31 South, Range 31 East; then east to the southeast corner of Section 13, Township 31 South, Range 31 East; then north along the range line common to Range 31 East and Range 32 East, Mount Diablo Base and Meridian, to the northwest corner of Section 6, Township 29 South, Range 32 East; then east to the southwest corner of Section 31, Township 28 South, Range 32 East; then north along the range line common to Range 31 East and Range 32 East to the northwest corner of Section 6, Township 28 South, Range 32 East, then west to the southeast corner of Section 36, Township 27 South, Range 31 East, then north along the range line common to Range 31 East and Range 32 East to the Kern-Tulare County boundary: | | | | | | |
| Kings County | 9/25/2025 | (
) | | | | |
| Madera County | 10/27/2025 | (
) | | | | |
| Merced County | 10/27/2025 | (
) | | | | |
| San Joaquin County | 10/27/2025 | (
) | | | | |
| Stanislaus County | 10/27/2025 | (
) | | | | |
| Tulare County | 10/27/2025 | (
) | | | | |
| | | | | | | |
| * * * * * * * | | | | | | |