Attorney General Clark Challenges Unlawful Rescission of Landmark 2009 Greenhouse Gas Endangerment Finding

Coalition of States, Counties, and Cities Across the Country Mount Legal Challenge in Opposition to EPA's Unlawful Rollback

Attorney General Charity Clarktoday joined a coalition of24 states, the District of Columbia, the U.S. Virgin Islands, and 12cities and counties to challenge the U.S. Environmental Protection Agency's unlawful attempt to rescind its 2009 Endangerment Finding - the agency's seminal determination that greenhouse gas pollution from motor vehicles drives climate change and endangers public health and welfare.

The 2009 Endangerment Finding was the direct result of the landmark 2007 Supreme Court decision in Massachusetts v. EPA , which confirmed that the Clean Air Act authorizes EPA to regulate greenhouse gas emissions that endanger public health and welfare. Based on years of rigorous scientific analysis and review, EPA in 2009 determined that emissions from motor vehicles contribute to air pollution that harms public health and welfare. EPA then set federal standards, which have led to significant reductions in motor vehicle greenhouse gas emissions.

Now, almost two decades later, EPA has rushed a rulemaking process to rescind the Endangerment Finding and repeal all motor vehicle greenhouse gas standards, blatantly disregarding the law and science. EPA's rescission is based on flawed interpretations of the law - previously rejected by the Supreme Court - that the agency lacks authority to regulate greenhouse gas emissions. The rescission also ignores decades of peer-reviewed scientific evidence confirming the reality and severity of climate change. By eliminating all existing and future federal motor vehicle greenhouse gas emission standards, the rule violates EPA's legal obligations, fundamental principles of administrative law, and the agency's mission to protect public health and welfare.

Today's lawsuit is the latest action taken by Attorney General Clark and the coalition in their ongoing effort to fight back against EPA's unlawful rescission of the 2009 Endangerment Finding. In the fall of 2025, 23 attorneys general and seven counties and cities submitted two comment letters urging EPA to abandon the proposal, arguing that it would violate settled law, clear Supreme Court precedent, and scientific consensus, endanger hundreds of millions of Americans-particularly communities disproportionately burdened by environmental harms-and cause unprecedented disruption to the regulatory landscape with catastrophic consequences for residents, industries, natural resources, and public investments.

Joining Attorney General Clark in filing this challenge are the attorneys general of Arizona, California, Colorado, Connecticut, Delaware, the District of Columbia, Hawai'i, Illinois, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nevada, New Jersey, New Mexico, New York, North Carolina, Oregon, Rhode Island, Virginia, Washington, Wisconsin, and the United States Virgin Islands, as well as the governor of Pennsylvania, the cities of Albuquerque, New Mexico; Boston, Massachusetts; Chicago, Illinois; Cleveland, Ohio; Columbus, Ohio; Los Angeles, California; and New York, New York; and the counties of Harris, Texas; Martin Luther King, Jr., Washington; and Santa Clara, California; and the Cities and Counties of Denver, Colorado, and San Francisco, California.

A copy of the petition is available on our website.

CONTACT: Amelia Vath, Senior Advisor to the Attorney General, 802-828-3171