End of an (Endangerment) Era

By Sukhmani K. Singh, Christopher P. Colyer, and Sean M. Sherlock

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

The EPA’s 2026 final rule eliminates the 2009 Endangerment Finding as well as all federal GHG emission standards for model year 2012-2027 vehicles and beyond.⁶ The final rule also eliminates associated compliance programs, reporting requirements, credit mechanisms, and “off-cycle” credits (including credits tied to start-stop vehicle systems).⁷ The EPA now asserts that CAA Section 202(a) does not authorize the EPA to regulate GHG emissions from motor vehicles for purposes of addressing global climate change and that the 2009 interpretation exceeded statutory authority. Notably, the EPA now finds that even if the United States were to eliminate all GHG emissions from all vehicles, there would be no material impact on global climate indicators through 2100.⁸

The repeal of the Endangerment Finding represents a watershed moment in U.S. environmental law. For nearly 16 years, the finding served as the cornerstone of federal greenhouse gas regulation under the CAA. Its elimination signals a dramatic recalibration of administrative authority over climate policy and likely tees up a new phase of litigation over the scope of federal environmental regulatory power.