On February 12, 2026, the U.S. Environmental Protection Agency (EPA) announced the repeal of the 2009 Greenhouse Gas (GHG) Endangerment Finding and the elimination of all federal GHG emission standards for motor vehicles and engines.1 The EPA characterized the action as the “single largest deregulatory action in U.S. history.”2 This development marks a fundamental shift in federal climate policy under the Clean Air Act (CAA) and is expected to trigger immediate and extensive litigation.

In Massachusetts v. EPA, the U.S. Supreme Court held that GHGs qualify as “air pollutants” under the CAA and that the EPA must determine whether emissions from new motor vehicles cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare under CAA Section 202(a).3 Following this decision, on December 7, 2009, the EPA issued two findings. First, the EPA classified six different GHGs as threatening public health and welfare. Second, the EPA determined that emissions from new motor vehicles contribute to that endangerment.4 Although the findings themselves imposed no direct regulatory requirements, they served as the legal predicate for GHG emission standards for light-duty and heavy-duty vehicles, and later for other CAA programs affecting statutory sources. In 2012, the U.S. Circuit Court of Appeals for the District of Columbia upheld the Endangerment Finding and related regulations.5

Reprinted courtesy of Sukhmani K. Singh, Snell & Wilmer, Christopher P. Colyer, Snell & Wilmer and Sean M. Sherlock, Snell & Wilmer

Ms. Singh may be contacted at ssingh@swlaw.com
Mr. Colyer may be contacted at ccolyer@swlaw.com
Mr. Sherlock may be contacted at ssherlock@swlaw.com