EPA repealed most provisions of the 2024 Carbon Pollution Standards for greenhouse gas (GHG) emissions from fossil fuel-fired electric generating units (EGUs), based on a reevaluation of the best system of emission reduction (BSER) for specified subcategories. EPA repealed emission guidelines for: existing fossil fuel-fired steam-generating units; the carbon capture and sequestration/storage (CCS)-based standards for coal-fired steam generating units undertaking a large modification; and the CCS-based standards for new base load stationary combustion turbines. EPA also issued a supplemental proposal soliciting comment on additional reasons to rescind all GHG emission requirements for fossil fuel-fired EGUs.