Attorney General Mayes Condemns the Illegal Rescission of EPA’s Landmark 2009 Greenhouse Gas Endangerment Finding

Rushed Rescission Rule Ignores Decades of Law and Science, Prioritizing Profit over the Health and Welfare of All Americans

PHOENIX — Attorney General Kris Mayes today issued the following statement in response to the U.S. Environmental Protection Agency’s (EPA) final rule rescinding the 2009 Endangerment Finding, which determined that greenhouse gas emissions from motor vehicles contribute to air pollution that drives climate change and endangers public health and welfare.

“The EPA’s decision to rescind the Endangerment Finding is unlawful, reckless, and flatly at odds with decades of settled law and science,” said Attorney General Kris Mayes. “By rescinding the Endangerment Finding, the EPA is reviving an argument the Supreme Court has already rejected and ignoring overwhelming scientific evidence. This rule abandons the agency’s fundamental responsibility to protect Americans from real and worsening environmental harm—all while putting industry profits ahead of Arizonans' health.”

The 2009 Endangerment Finding was the direct result of the landmark 2007 Supreme Court decision in Massachusetts v. EPA, which confirmed EPA’s authority under the Clean Air Act to regulate greenhouse gas emissions that threaten public health and welfare. In response to that opinion and after years of scientific review, EPA confirmed in 2009 that greenhouse gas emissions from motor vehicles contribute to air pollution that harms public health and welfare in numerous ways. The agency then set standards to limit motor vehicle greenhouse gas emissions.  

EPA’s rescission of the Endangerment Finding rests on the flawed assertion—soundly rejected by the Supreme Court—that it lacks legal authority to regulate greenhouse gas emissions and ignores long standing scientific evidence that greenhouse gases endanger public health and welfare. The rule eliminates all existing and future federal greenhouse gas standards for vehicles, violating the agency’s legal obligations and fundamental responsibility to protect public health and welfare from environmental harm.  

In August 2025, following the Trump Administration’s initial proposal to repeal the Endangerment Finding, AG Mayes testified before the EPA, highlighting the illegality of the proposed rescission, the agency’s reliance on flawed and unscientific sources to deny climate change, and its failure to acknowledge climate impacts on everyday life.