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Proposed Rule2025-174992025-09-11

Air Plan Approval; Montana; Regional Haze Plan for the Second Implementation Period; Prong 4 (Visibility) for the 2015 8-Hour Ozone National Ambient Air Quality Standard

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA) is proposing to approve the regional haze state implementation plan (SIP) submission submitted by the State of Montana on August 10, 2022, under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. Montana's 2022 SIP submission addresses the requirement that states revise their long-term strategies every implementation period to make 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. Montana's 2022 SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is also proposing to approve the prong 4 visibility portion of Montana's October 1, 2018 Infrastructure SIP submission for the 2015 ozone National Ambient Air Quality Standards (NAAQS). The EPA is taking these actions pursuant to the CAA.

Action & Dates

Action
Proposed rule.
Dates
Written comments must be received on or before October 14, 2025.

CFR References

Topics

Air pollution controlCarbon monoxideEnvironmental protectionGreenhouse gasesIncorporation by referenceIntergovernmental relationsLeadNitrogen dioxideOzoneParticulate matterReporting and recordkeeping requirementsSulfur oxidesVolatile organic compounds

Public Comment

Comments Close
2025-10-14

Document Excerpt

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-12597-01-R8] AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: The Environmental Protection Agency (EPA) is proposing to approve the regional haze state implementation plan (SIP) submission submitted by the State of Montana on August 10, 2022, under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. Montana's 2022 SIP submission addresses the requirement that states revise their long-term strategies every implementation period to make 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. Montana's 2022 SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is also proposing to approve the prong 4 visibility portion of Montana's October 1, 2018 Infrastructure SIP submission for the 2015 ozone National Ambient Air Quality Standards (NAAQS). The EPA is taking these actions pursuant to the CAA. DATES: Written comments must be received on or before October 14, 2025. ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-OAR-2024-0608, to the Federal Rulemaking Portal: https://www.regulations.gov . Follow the online instructions for submitting comments. Once submitted, comments cannot

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Related Documents

Other Federal Register documents from the same docket.

Full Document

Citation: 90 FR 43958