The Environmental Protection Agency (EPA) is approving a source-specific revision to the Wyoming State Implementation Plan (SIP) that provides an alternative to Best Available Retrofit Technology (BART) for Unit 3 at the Naughton Power Plant ("the SIP revision") that is owned and operated by PacifiCorp. The EPA finds that the BART alternative for Naughton Unit 3 provides greater reasonable progress toward natural visibility conditions than BART in accordance with the requirements of section 110 of the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR). The SIP revision was submitted by the State of Wyoming on November 28, 2017.