Pursuant to the federal Clean Air Act (CAA or Act), the Environmental Protection Agency (EPA) is finalizing its affirmation, with amendments, of an intrastate sulfur dioxide (SO<INF>2</INF>) trading program as an alternative to best available retrofit technology (BART) requirements for certain sources in Texas. This action finalizes the August 2018 proposed affirmation and November 2019 supplemental notice of proposed rulemaking (SNPRM) concerning certain aspects of a final rule published on October 17, 2017, partially approving the 2009 Texas Regional Haze State Implementation Plan (SIP) submission and promulgating a Federal Implementation Plan (FIP) for Texas to address certain outstanding CAA regional haze requirements for the first implementation period.