Last mentioned: Mar 19, 2026
Multi-State Lawsuit Filed
24 states and 10 cities sue to block the repeal in federal court.
Multi-State Lawsuit Filed
24 states and 10 cities sue to block the repeal in federal court.
EPA Repeals Finding
The agency formally rescinds the 2009 determination.
EPA Repeals Finding
The agency formally rescinds the 2009 determination.
Endangerment Finding Issued
EPA formally determines GHGs threaten public health and welfare.
Endangerment Finding Issued
EPA officially finds that six greenhouse gases threaten public health.
Massachusetts v. EPA
Supreme Court rules GHGs are pollutants under the Clean Air Act.
Massachusetts v. EPA
Supreme Court rules EPA has authority to regulate GHGs if they endanger health.
A coalition of 24 states and 10 cities has filed a lawsuit against the EPA to block the repeal of the 2009 endangerment finding. The legal challenge argues that removing the scientific basis for greenhouse gas regulation is arbitrary and threatens public health.
A coalition of 24 states and 10 cities has filed a major lawsuit against the Environmental Protection Agency following its repeal of the 2009 greenhouse gas endangerment finding. The legal challenge aims to preserve the foundational authority for federal climate regulations under the Clean Air Act.