Air Plan Approval; Missouri; Moderate Attainment Plan Elements for the 2015 8-Hour Ozone Standard for the Missouri Portion of the St. Louis Nonattainment Area

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-R07-OAR-2026-5842; FRL-13521-01-R7] ( printed page 52617) AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: The Environmental Protection Agency (EPA) is proposing to approve portions of a state implementation plan (SIP) revision submitted by the State of Missouri on September 6, 2023, as meeting Clean Air Act (CAA) requirements for the 2015 8-hour ozone national ambient air quality standards (NAAQS) in the Missouri portion of the St. Louis, MO-IL bi-state nonattainment area. Specifically, the EPA is proposing approval of the submitted vehicle inspection and maintenance (I/M) program, nonattainment new source review (NNSR) program, and reasonably available control technology (RACT) determinations for major sources of volatile organic compounds (VOC) and Nitrogen Oxides (NO X ) SIP elements as meeting applicable Moderate nonattainment area requirements for the 2015 8-hour ozone NAAQS. The EPA will address the remaining SIP elements in a separate action. DATES: Comments must be received on or before September 14, 2026. ADDRESSES: You may send comments, identified by Docket ID No. EPA-R07-OAR-2026-5842 to https://www.regulations.gov . Follow the online instructions for submitting comments. Instructions: All submissions received must include the Docket ID No. for this rulemaking. Comments received will be posted without change to https://www.regulations.gov , including any personal information provide…