Last mentioned: Mar 19, 2026
State Coalition Lawsuit
US states file a joint lawsuit to block the EPA's repeal in federal court.
EPA Repeal Announcement
The Trump EPA formally moves to rescind the 2009 Endangerment Finding.
Endangerment Finding Issued
EPA officially finds that six greenhouse gases threaten the health of current and future generations.
Massachusetts v. EPA
Supreme Court rules EPA must regulate GHGs if they are found to endanger public health.
A coalition of US states has filed a high-stakes lawsuit against the Environmental Protection Agency to block the repeal of the 2009 Endangerment Finding. The legal challenge argues that the administration is ignoring established science to dismantle the foundation of federal greenhouse gas regulations.