Air Plan Approval; Pennsylvania; Redesignation of the Warren County Nonattainment Area to Attainment and Approval of the Area's Maintenance Plan for the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality Standard

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 Parts 52 and 81 [EPA-R03-OAR-2026-1685; FRL-13024-01-R3] ( printed page 48034) AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: The Environmental Protection Agency (EPA) is proposing to approve a state implementation plan (SIP) revision and redesignation request submitted on September 19, 2025 by the Pennsylvania Department of Environmental Protection (PADEP). The SIP revision asks the EPA to redesignate the Warren County, Pennsylvania area from nonattainment to attainment for the 2010 1-hour primary sulfur dioxide (SO 2 ) national ambient air quality standard (NAAQS). The revision also asks the EPA to approve into the SIP the Commonwealth's maintenance plan for the 2010 1-hour primary SO 2 NAAQS for the Warren County area. Furthermore, Pennsylvania requests that the EPA correct source-specific requirements for United Refining Company within the Pennsylvania SIP that were previously included in error. This proposed action is being taken under the Clean Air Act (CAA). DATES: Written comments must be received on or before August 31, 2026. ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R03-OAR-2026-1685 at www.regulations.gov , or via email to gordon.mike@epa.gov . For comments submitted at Regulations.gov, follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. For either manner of submission, the EPA may publish any c…