Data / Federal rules / 2025-17045

Approval of Air Quality Implementation Plans; California; Regional Haze State Implementation Plan for the Second Implementation Period

The Environmental Protection Agency published this final rule in the Federal Register on September 5, 2025. It took effect on October 6, 2025.

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What the agency says

The Environmental Protection Agency (EPA) is approving the regional haze state implementation plan (SIP) revision submitted by California on August 9, 2022 (hereinafter the "2022 California Regional Haze Plan" or "the Plan"), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. The Plan addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The Plan also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to CAA sections 110 and 169A.

Key facts

Document number: 2025-17045
Type: Final rule
Action: Final rule
Agency: Environmental Protection Agency
Published: September 5, 2025
Takes effect: October 6, 2025
Dates: This final rule is effective on October 6, 2025.
Docket: EPA-R09-OAR-2025-0203; FRL-12755-02-R9
Code of Federal Regulations: 40 CFR 52
Topics: Air pollution control; Environmental protection; Incorporation by reference; Nitrogen dioxide; Ozone; Particulate matter; Sulfur oxides
Pages: 4

The document on federalregister.gov PDF

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Everything from the Environmental Protection Agency · Rules on air pollution control · Rules on environmental protection · Rules on incorporation by reference · Published in September 2025

Read from the Federal Register API, last updated 2026-10-23. The document on federalregister.gov is the official record; dates and dockets can change through later corrections. Free to reuse with credit to SpecStream under CC BY 4.0.