On December 20, 2018, the EPA proposed revised Standards of Performance for Greenhouse Gas Emissions From New, Modified, and Reconstructed Stationary Sources: Electric Generating Units, found at 40 CFR part 60, subpart TTTT. The EPA proposed to amend the previous determination that the best system of emission reduction (BSER) for newly constructed coal-fired steam generating units (i.e., EGUs) is partial carbon capture and storage. Instead, the proposed revised BSER for this source category is the most efficient demonstrated steam cycle (e.g., supercritical steam conditions for large units and subcritical steam conditions for small units) in combination with the best operating practices. On January 13, 2021, the EPA finalized the portion of the proposal that provided a framework for criteria for making a significant contribution finding (SCF) for greenhouse gas (GHG) emissions from a source category, for the purpose of regulating those emissions under section 111(b) of the Clean Air Act (CAA). On April 5, 2021, the court granted the EPA’s request for a voluntary vacatur and remand of the SCF final rule. The EPA continues to review comments on the BSER portion of the 2018 proposed amendments and whether any follow-up action is appropriate to address the SCF vacatur and remand. Any future actions will follow the guidance under Executive Order 13990.