The Environmental Protection Agency (EPA) is approving, under the Clean Air Act (CAA), a revision to Ohio's State Implementation Plan (SIP) as requested by the Ohio Environmental Protection Agency (OEPA) on March 30, 2011, and amended on August 22, 2019 and December 10, 2019. The revision to Ohio's SIP modifies Ohio's Prevention of Significant Deterioration (PSD) program to establish emission thresholds for determining when stationary source projects are potentially subject to Ohio's PSD permitting requirements for greenhouse gas (GHG) emissions. Consistent with Ohio's requests, EPA is taking no action on paragraphs (B), (C), and (D) of Ohio's GHG rule.