Air Plan Approval; Montana; Regional Haze Plan for the Second Implementation Period

Document Headings Document headings vary by document type but may contain the following: the agency or agencies that issued and signed a document the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to the agency docket number / agency internal file number the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Environmental Protection Agency 40 CFR Part 52 [EPA-R08-OAR-2024-0608; FRL-12597-02-R8] AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: The Environmental Protection Agency (EPA) is approving a regional haze state implementation plan (SIP) revision submitted by the State of Montana on August 10, 2022 (Montana's 2022 SIP submission), as satisfying applicable requirements under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. The EPA is also finalizing approval of the prong 4 visibility portion of Montana's October 1, 2018, Infrastructure SIP submission for the 2015 ozone National Ambient Air Quality Standard (NAAQS). The EPA is taking this action pursuant to the CAA. DATES: This rule is effective on December 29, 2025. ADDRESSES: The EPA has established a docket for this action under Docket ID No. EPA-R08-OAR-2024-0608. 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 (CBI) 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 …