Air Plan Approval; Michigan; Infrastructure SIP Requirements for the 2015 Ozone NAAQS; Michigan State Board Requirements

The Environmental Protection Agency (EPA) is approving an element of a State Implementation Plan (SIP) submission from the Michigan Department of Environment, Great Lakes, and Energy (Michigan) regarding the infrastructure requirements of section 110 of the Clean Air Act (CAA) for the 2015 ozone National Ambient Air Quality Standards (NAAQS). The infrastructure requirements ensure that the structural components of each State's air quality management program are adequate to meet CAA requirements. This action pertains to CAA section 110(a)(2)(E)(ii). The EPA received comments on its November 20, 2025, proposed rule and withdrew the accompanying direct final rule. After considering the comments, the EPA is approving this element of Michigan's March 8, 2019, SIP submission.