SUPPLEMENTARY INFORMATION:

Throughout this document, the terms “we”, “us,” and “our” refer to the EPA. This SUPPLEMENTARY INFORMATION section is organized as follows:

Table of Contents

I. Background

A. Description of a SIP

B. How the EPA Enforces SIPs

C. How the State and the EPA Update the SIP

D. How the EPA Compiles the SIPs

E. How the EPA Organizes the SIP Compilation

F. Where You Can Find a Copy of the SIP Compilation

G. The Format of the California Identification of Plan Sections

H. When a SIP Revision Becomes Federally Enforceable

I. The Historical Record of SIP Revision Approvals

II. What the EPA Is Doing in This Action

III. Incorporation by Reference

IV. Statutory and Executive Order Reviews

I. Background

A. Description of a SIP

Each State has a SIP containing, among other things, the control measures and strategies used to attain and maintain the national ambient air quality standards (NAAQS). The SIP is extensive, containing such elements as air pollution control regulations, emission inventories, monitoring networks, attainment demonstrations, and enforcement mechanisms.

B. How the EPA Enforces SIPs

Each State must formally adopt the control measures and strategies to attain and maintain the NAAQS after the public has had an opportunity to comment on them. They are then submitted to the EPA as requested SIP revisions upon which the EPA must formally act. Once these control measures and strategies are approved by the EPA, after notice and comment rulemaking, they are incorporated into the federally approved SIP and are identified in part 52 (Approval and Promulgation of Implementation Plans), title 40 of the Code of Federal Regulations (40 CFR part 52). The EPA uses the process of incorporation by reference (IBR) to incorporate material into the CFR by referencing the original document(s) without publishing the full text of the material. The actual State regulations approved by the EPA are not reproduced in their entirety in 40 CFR part 52 but are “incorporated by reference,” which means that the EPA has approved a given State regulation with a specific effective date. This format allows both the EPA and the public to know which measures are contained in a given SIP and to help determine whether the State is enforcing the regulations. This format also assists the EPA and the public in taking enforcement action, should a State not enforce its SIP-approved regulations.

C. How the State and the EPA Update the SIP

The SIP is a dynamic document, which the State can revise as necessary to address the unique air pollution problems in the State. Therefore, the EPA must periodically take action on State SIP revisions containing new and/or revised regulations and other materials in order to make them part of the federally-approved SIP. The EPA establishes a docket for its actions using a unique Docket Identification Number, which is listed in each action. These dockets and the complete submissions are available for viewing on www.regulations.gov.

On May 22, 1997 (62 FR 27968), the EPA revised the formatting procedures for incorporating by reference federally-approved SIP revisions, as a result of consultations between the EPA and the Office of the Federal Register. These procedures include: (1) a revised SIP document for each State that would use the IBR process under the provisions of title 1 CFR part 51; (2) a revised mechanism for announcing the EPA's approval of revisions to an applicable SIP and updating both the document that has gone through the IBR process and the CFR; and (3) a revised format of the “Identification of Plan” sections for each applicable subpart in 40 CFR part 52 to reflect these revised IBR procedures. The description of the revised SIP document, IBR procedures, and “Identification of plan” format are discussed in further detail in the May 22, 1997 (62 FR 27968) Federal Register document. We have taken action to revise the format for many State SIPs, see, e.g.,40 CFR 52.1470 and 52.1490 (“Identification of plan” and “Original identification of plan” sections for the State of Nevada SIP), and take a fifth and final step today toward revising the format of the California SIP.

D. How the EPA Compiles the SIPs

Under the revised SIP format, the federally-approved regulations, source-specific requirements, and nonregulatory provisions (entirely or portions of) submitted by each State agency have been compiled by the EPA into a “SIP compilation.” The SIP compilation contains the regulations, source-specific requirements, and nonregulatory and quasi-regulatory provisions approved by the EPA through previous rulemaking actions published in the Federal Register .

E. How the EPA Organizes the SIP Compilation

Each compilation contains three parts. Part one contains the regulations, part ( printed page 70125) two contains the source-specific requirements, and part three contains the nonregulatory and quasi-regulatory provisions that have been approved by the EPA as part of the SIP. Each part consists of a table or tables of identifying information for each SIP-approved regulation, each SIP-approved source-specific requirement, and each nonregulatory or quasi-regulatory SIP provision. The EPA Regional Offices have the primary responsibility for updating the compilations and ensuring their accuracy.

F. Where You Can Find a Copy of the SIP Compilation

EPA Region IX has developed and will maintain the SIP compilation for California. A copy of the full text of California's regulatory and source-specific SIP compilation will also be maintained at NARA.

G. The Format of the California Identification of Plan Sections

Given the size of the California SIP, the EPA is revising the format of the California SIP in a phased manner. On May 26, 2016 (81 FR 33397), the EPA took the first action to revise the format of the “Identification of plan” section in subpart F in accordance with the revised format described in section I.C. of this document. Through the first action, we revised the heading of 40 CFR 52.220 to read, “Identification of plan—in part,” and added an introductory paragraph to convey our division of the California “Identification of plan” section into two sections:

• Amended40 CFR 52.220 (renamed “Identification of plan—in part”), which would continue for the time being to function as it has in the past to list past and newly-approved air district rules, local ordinances, source-specific requirements, and nonregulatory and quasi-regulatory provisions and which lists State statutes and State regulations approved on or prior to April 1, 2016; and
• New40 CFR 52.220a (“Identification of plan—in part”), which lists the State statutes and State regulations approved as part of the California SIP as of April 1, 2016, using the new table format.

This meant that subsequent EPA approvals of air district rules, local ordinances, source-specific requirements, and nonregulatory and quasi-regulatory provisions would continue to be promulgated in 40 CFR 52.220 using the paragraph format whereas subsequent EPA approvals of State statutes and State regulations would be promulgated in 40 CFR 52.220a using the table format. In preparation for future actions to revise the format of the remaining portions of the California SIP, the May 26, 2016 action also organized 40 CFR 52.220a into five paragraphs: (a) Purpose and scope; (b) Incorporation by reference; (c) EPA-approved regulations; (d) EPA-approved source-specific requirements; and (e) EPA-approved nonregulatory provisions and quasi-regulatory measures. “Nonregulatory provisions and quasi-regulatory measures” refers to items such as transportation control measures, certain nonregulatory statutory provisions, control strategies, and monitoring networks.

Our phased approach to converting the format of the California SIP anticipated that, over time, as the EPA completes further rulemaking actions to convert the format of the California SIP, 40 CFR 52.220a would include a growing number of air district rules, local ordinances, source-specific requirements, and nonregulatory and quasi-regulatory provisions. On June 4, 2025 (90 FR 23618), the EPA took a second action to revise the format of the California SIP by converting the format for local ordinances and air district rules approved on or prior to April 17, 2025, for the following air districts: Amador Air District, Antelope Valley Air Quality Management District (AQMD), Bay Area AQMD, Butte County AQMD, Calaveras County Air Pollution Control District (APCD), Colusa County APCD, Eastern Kern APCD, and El Dorado County AQMD.

A third action was taken on July 7, 2025 (90 FR 29934) that converted the format for the nonregulatory provisions and quasi-regulatory measures portion of the California SIP approved on or prior to July 3, 2025. On August 21, 2025 (90 FR 40896), the EPA took a fourth action to revise the format of the California SIP by converting the format for source-specific requirements and air district rules approved on or prior to June 30, 2025, for the following air districts: Feather River Air Quality Management District (AQMD), Glenn County Air Pollution Control District (APCD), Great Basin Unified APCD, Imperial County APCD, Lake County AQMD, Lassen County APCD, Mariposa County APCD, Mendocino County AQMD, Modoc County APCD, Monterey Bay Air Resources District, North Coast Unified AQMD, Northern Sierra AQMD, Northern Sonoma County APCD, San Diego County APCD, San Luis Obispo County APCD, Santa Barbara County APCD, Shasta County AQMD, Siskiyou County APCD, Tehama County APCD, Tuolumne County APCD, and Yolo-Solano County AQMD.

In this fifth action to revise the format of the California SIP, we are converting the format and publishing the tables listing EPA-approved rules adopted by the following six California air districts: Mojave Desert AQMD, Placer County APCD, Sacramento Metropolitan AQMD, San Joaquin Valley Unified APCD, South Coast AQMD, and Ventura County APCD. This format revision involves materials approved on or before August 31, 2026 that are part of the current applicable SIP.

Through this fifth and final action, the EPA is completing the conversion process for the California SIP. As anticipated in the earlier actions, the EPA is redesignating 40 CFR 52.220a as 40 CFR 52.220 and renaming it simply “Identification of plan.” All subsequent actions by the EPA to approve California SIP revisions will be promulgated using the new table format. The revised format does not affect federal enforceability of the SIP and is consistent with the requirements of section 110(h)(1) of the Clean Air Act (CAA) concerning comprehensive SIP publication.

H. When a SIP Revision Becomes Federally Enforceable

All revisions to the applicable SIP become federally enforceable as of the effective date of the revisions to paragraphs (c), (d), or (e) of the applicable Identification of Plan section found in each subpart of 40 CFR part 52.

I. The Historical Record of SIP Revision Approvals

To facilitate enforcement of previously-approved SIP provisions and provide a smooth transition to the new SIP processing system, the EPA is redesignating the “Identification of plan—in part” section for California appearing in 40 CFR 52.220 as 40 CFR 52.250 and renaming the newly-redesignated section as “Original identification of plan.” After an initial one or two-year period, the EPA will review its experience with the new SIP processing system and decide whether to retain the “Original identification of plan” section for some further period.

II. What the EPA Is Doing in This Action

In this action, the EPA is revising the format for portions of the applicable California SIP related to the rules from the following six air districts: Mojave Desert AQMD, Placer County APCD, Sacramento Metropolitan AQMD, San Joaquin Valley Unified APCD, South Coast AQMD, and Ventura County APCD. This format revision involves materials approved on or before August ( printed page 70126) 31, 2026, that are part of the current applicable SIP.

This action constitutes a “housekeeping” exercise to ensure that all EPA-approved revisions to the State programs that have occurred are accurately reflected in 40 CFR part 52. The requirements that apply to States and that relate to SIPs and SIP revisions are set forth in the Clean Air Act and in the EPA's regulations at 40 CFR part 51. When the EPA receives a formal SIP revision request, the Agency must publish the proposed revision in the Federal Register and provide for public comment before approval.

The EPA has determined that this rule falls under the “good cause” exemption in section 553(b)(B) of the Administrative Procedure Act (APA) which, upon finding “good cause,” authorizes agencies to dispense with public participation and section 553(d)(3) which allows an agency to make a rule effective immediately, thereby avoiding the 30-day delayed effective date otherwise provided for in the APA. This action simply reformats and recodifies provisions which are already in effect as a matter of law in Federal and approved State programs. Under section 553 of the APA, an agency may find good cause where notice and public procedure are “impractical, unnecessary, or contrary to the public interest.” Public comment is “unnecessary” and “contrary to the public interest” for this action because the EPA is merely reformatting and recodifying existing law. Immediate notice in the CFR benefits the public by removing outdated citations and making the IBR format clearer and more user-friendly.

III. Incorporation by Reference

In this rule, the EPA is finalizing regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is reformatting the materials incorporated by reference in previous rulemakings on submittals of the California SIP and SIP revisions, as described in section II of this preamble. The EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the appropriate EPA office (see the ADDRESSES section of this preamble for more information).

IV. Statutory and Executive Order Reviews

A. General Requirements

This action does not impose additional requirements beyond those previously approved into the SIP and already 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 is an administrative action related to State program approval;
• 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 CAA.

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).

B. Submission to Congress and the Comptroller General

The Congressional Review Act (5 U.S.C. 801 et seq.), as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy of the rule, to each House of the Congress and to the Comptroller General of the United States. 5 U.S.C. 808 allows the issuing agency to make a rule effective sooner than otherwise provided by the CRA if the agency makes a good cause finding that notice and public procedure is impracticable, unnecessary or contrary to the public interest. This action simply reformats and recodifies provisions that are already in effect as a matter of law in Federal and approved State programs ( See5 U.S.C. 802(2)). As stated previously, the EPA has made such a good cause finding, including the basis for that finding, and established an effective date of November 6, 2026. The EPA will submit a report containing this rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of the rule in the Federal Register . This action is not a “major rule” as defined by 5 U.S.C. 804(2).

C. Petitions for Judicial Review

The EPA has also determined that the provisions of section 307(b)(1) of the CA A pertaining to petitions for judicial review are not applicable to this action. Prior EPA rulemaking actions for each individual component of the California SIP compilation had previously afforded interested parties the opportunity to file a petition for judicial review in the United States Court of Appeals for the appropriate circuit within 60 days of such rulemaking action. Thus, the EPA believes judicial review of this action under section 307(b)(1) is not available.

For the reasons stated in the preamble, the Environmental Protection Agency amends part 52, chapter I, title 40 of the Code of Federal Regulations as follows: