Proposed rule · 2026-16571

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

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<INF>X</INF>) 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.