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

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03/19/2026

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

Connecticut Co-Leads National Coalition of States, Counties, and Cities Mounting Legal Challenge in Opposition to EPA's Unlawful Anti-Science Rollback

(Hartford, CT) - Attorney General William Tong today led a coalition of 24 states and 12 counties and cities to challenge the U.S. Environmental Protection Agency's unlawful attempt to rescind its science-based 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 Trump EPA has ignored the law and ignored the science in its reckless rush to fulfill the wishes of the fossil fuel industry. Rescinding the Endangerment Finding means bigger profits for the world's biggest polluters, while the rest of us are left more vulnerable to extreme weather, extreme heat and rising sea levels. Connecticut is leading states and cities across the country in suing today and we're going to fight with everything we've got," said Attorney General Tong.

"The Endangerment Finding was a well-reasoned, scientifically sound decision that validated something we're seeing firsthand: climate change is impacting our public health and safety today while imposing significant and increasing costs on Connecticut residents," Department of Energy and Environmental Protection Commissioner Katie Dykes said. "To deny that reality increases the vulnerability of our state to these impacts today, and for future generations. Wildfires, historic flooding, cold snaps, and heat waves-these are no longer rare events; they're our new normal. As the federal government retreats from its responsibilities to protect the public, states like Connecticut will step up to do what it can to prevent the worst impacts of climate change while also investing in resilience and disaster recovery."

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, in 2009 EPA determined that greenhouse gas emissions from motor vehicles contribute to air pollution that harms public health and the environment. EPA then set federal standards to limit those emissions, leading to significant reductions from motor vehicles.

Now, almost two decades later, EPA has rushed a rulemaking process to rescind the Endangerment Finding and repeal all motor vehicles greenhouse gas standards, blatantly disregarding well-established 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 vehicle greenhouse gas emission standards, the rule violates EPA's legal obligations, fundamental principles of administrative law, and its mission to protect public health and welfare.

Today's lawsuit is the latest action led by Attorney General Tong and the coalition in the ongoing effort to fight back against EPA's unlawful rescission of the 2009 Endangerment Finding. In the fall of 2025, Attorney General Tong co-led a coalition of 23 attorneys general and seven counties and cities submitting 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.

The lawsuit is co-led by the attorneys general of California, Connecticut, Massachusetts, and New York and joined by the attorneys general of Arizona, Colorado, Delaware, Hawai'i, Illinois, Maine, Maryland, Michigan, Minnesota, New Jersey, New Mexico, Nevada, North Carolina, Oregon, Rhode Island, Vermont, Virginia, Washington, Wisconsin, the District of Columbia. In addition, this challenge is joined by Pennsylvania Governor Josh Shapiro; City of Boston, Massachusetts; City of Chicago, Illinois; City of Cleveland, Ohio; City of Columbus, Ohio; City and County of Denver, Colorado; City of Los Angeles, California; City of New York, New York; City and County of San Francisco, California; County of Santa Clara, California; and Harris County, Texas.

Assistant Attorneys General William Dornbos, Scott Koschwitz and Special Assistant Attorney General Jessica Gibree and Deputy Associate Attorney General Matthew Levine, Chief of the Environment Section, are assisting the Attorney General in this matter.
Twitter: @AGWilliamTong Facebook: CT Attorney General

Media Contact:

Elizabeth Benton [email protected]

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