The Environmental Protection Agency (EPA) is approving SIP revisions submitted by the States of Maine and New Hampshire as meeting the Clean Air Act (CAA) requirement that each State Implementation Plan (SIP) contain adequate provisions to prohibit emissions that will significantly contribute to nonattainment or interfere with maintenance of the 2015 ozone NAAQS in any other state. This action is being taken in accordance with the Clean Air Act.

The Environmental Protection Agency (EPA) is approving state implementation plan (SIP) revisions submitted by the State of Tennessee, through the Tennessee Department of Environment and Conservation (TDEC), through letters dated February 26, 2020. Specifically, EPA is approving the removal of Tennessee's motor vehicle inspection and maintenance (I/M) program requirements for Davidson, Sumner, Rutherford, Williamson and Wilson Counties in Tennessee (also known as the Middle Tennessee Area) and Hamilton County (also known as the Chattanooga Area), from the federally-approved SIP.

The Environmental Protection Agency (EPA) is updating the regulatory materials incorporated by reference into the Washington State Implementation Plan (SIP). The regulations addressed in this action were previously submitted by the Washington Department of Ecology and approved by the EPA in prior rulemakings. This action is an administrative change that updates the SIP materials available for public inspection at the National Archives and Records Administration and the EPA Regional Office.

The Environmental Protection Agency (EPA) is withdrawing its proposed rule to approve Missouri's revisions to the state's open burning rule, as published in the Federal Register on January 13, 2020. By a letter to the EPA dated May 26, 2021, Missouri withdrew its request for approval of revisions to this rule in the state implementation plan (SIP).