Air Plan Approval; Pennsylvania; Adoption of Federal Implementation Plan Reasonably Available Control Technology Requirements for Keystone, Conemaugh, Homer City, and Montour Generating Facilities for the 1997 and 2008 Ozone National Ambient Air Quality Standards

The Environmental Protection Agency (EPA) is approving a portion of the state implementation plan (SIP) revisions submitted by the Commonwealth of Pennsylvania. The revisions being approved adopt nitrogen oxides (NO<INF>X</INF>) emission limits and requirements for the coal-fired electric generating units (EGUs) equipped with selective catalytic reduction (SCR) at the Keystone, Conemaugh, Homer City, and Montour facilities. The NO<INF>X</INF> limits address reasonably available control technology (RACT) requirements for these EGUs for the 1997 and 2008 ozone national ambient air quality standards (NAAQS) and address the deficiencies identified in EPA's August 16, 2022, disapproval of an earlier SIP submission. This action is being taken under the Clean Air Act (CAA).