Arizona Attorney General Kris Mayes announced on Mar. 19 that she has joined a coalition of states, counties, and cities in filing a lawsuit against the U.S. Environmental Protection Agency (EPA) over its decision to rescind the 2009 Endangerment Finding, which determined that greenhouse gas emissions from motor vehicles contribute to climate change and threaten public health.
The challenge comes as Arizona faces extreme heat warnings and rising temperatures, underscoring concerns about the impact of climate change on public health and safety. The lawsuit argues that the EPA’s move disregards established science and legal precedent, potentially accelerating climate change effects in Arizona and beyond.
“On the day we file this lawsuit, much of Arizona is under an extreme heat warning due to an unprecedented early heatwave that has spiked temperatures over twenty degrees above normal,” said Attorney General Mayes. “The science behind the 2009 Endangerment Finding is real and grounded in rigorous research. It is abundantly clear that greenhouse gas pollution has fueled climate change in our state and across the entire planet. The decision by the Trump administration to rescind the Endangerment Finding will only accelerate climate change. Putting the profits of the fossil fuel industry over the future of our planet is a failure of historic proportions and we will fight it with every tool we have.”
The original Endangerment Finding followed a Supreme Court ruling confirming EPA authority under the Clean Air Act to regulate greenhouse gases from vehicles. Since then, federal standards have led to reductions in vehicle emissions. The new rulemaking process by EPA seeks to eliminate these standards based on legal interpretations previously rejected by courts, according to Mayes’ office.
Recent years have seen record-breaking heat in Arizona; for example, more than 500 people died during Arizona’s hottest summer on record in 2023, with emergency rooms recording over 4,000 heat-related visits statewide. Wildfires have also increased in frequency and severity—such as last year’s Dragon Bravo Fire—which destroyed structures at Grand Canyon National Park.
Mayes joins attorneys general from more than twenty states as well as several major cities and counties nationwide in this legal action. In fall 2025, a coalition submitted comment letters urging EPA not to proceed with rescinding its findings or emission standards.
The Arizona Attorney General’s Office serves as Arizona’s chief legal office with statewide responsibilities for legal and protective services according to its official website. It addresses issues such as elder abuse, civil rights violations, unsolved crimes through its cold case unit according to its official website, participates in federal lawsuits including those related to fair housing and social media accountability according to its official website, offers advocacy for residents according to its official website, delivers comprehensive services statewide according to its official website, and is led by Kris Mayes—the state’s 27th attorney general and first mother in this role according to its official website.
Today’s lawsuit represents another step by Mayes’ office toward addressing environmental threats facing Arizonans while continuing broader efforts for community protection.
