The Environmental Protection Agency (EPA) is approving a State Implementation Plan (SIP) revision submitted by the State of Montana on March 25, 2020, addressing regional haze. Specifically, EPA is approving a SIP revision for the first implementation period of the Clean Air Act's (CAA) regional haze program that addresses the nitrogen oxides (NO<INF>X</INF>) and sulfur dioxide (SO<INF>2</INF>) Best Available Retrofit Technology (BART) requirements for two electric generating unit (EGU) facilities, as well as replaces portions of the Federal Implementation Plan (FIP) promulgated by EPA in 2012 (2012 regional haze FIP) addressing the NO<INF>X</INF>, SO<INF>2</INF>, and particulate matter (PM) BART requirements for two cement kilns and the PM BART requirements for the same two EGU facilities. Consistent with our approval of Montana's regional haze SIP revision, EPA is withdrawing, the portions of the FIP promulgated by EPA in the 2012 regional haze FIP addressing the NO<INF>X</INF>, SO<INF>2</INF>, and PM BART requirements for the two cement kilns and the PM BART requirements for the two EGU facilities. This action also addresses the United States Court of Appeals for the Ninth Circuit's June 9, 2015 vacatur and remand of portions of the FIP. EPA is finalizing this action pursuant to the CAA.