On September 17, 2026, EPA published its final rule repealing most of the 2024 Carbon Pollution Standards, a set of greenhouse gas emissions standards and guidelines for existing, modified, and new fossil fuel-fired power plants. EPA determined that the standards and guidelines were not a “best system of emissions reduction” under the relevant statute for a variety of reasons, including cost, effectiveness, and availability of emissions reduction technology. EPA also asserted that the 2024 rules violated the Supreme Court’s bar on “generation shifting,” announced in West Virginia v. EPA.
On the same day, EPA issued a supplemental proposal, explaining that it now reads Clean Air Act section 111 as not authorizing any EPA regulation of greenhouse gas emissions from power plants. EPA thus proposes extending its conclusions that it lacks authority to regulate greenhouse gas emissions from US vehicles — the basis of its rescission of the Endangerment Finding in February 2026 — to the second-largest sector of emissions in the US.
This analysis examines how EPA has explained its final repeal and supplemental proposal and explores vulnerabilities and areas of tension that challengers or commenters may identify.
Comments on EPA’s supplemental proposal are due on November 2, 2026.