Arizona Joins Multi-State Lawsuit Against EPA Over Climate Regulations

Mar 20, 2026, 2:22 AM

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Arizona has joined a coalition of over two dozen states, counties, and cities in a lawsuit against the US Environmental Protection Agency (EPA) challenging the recent rescission of the Endangerment Finding. This finding, established in 2009, recognized that greenhouse gas emissions from vehicles and other sources contribute to climate change and pose significant threats to public health and welfare.

The lawsuit, filed in the US Court of Appeals for the District of Columbia, asserts that the EPA's decision to roll back these regulations violates established law and scientific consensus on climate change. Arizona Attorney General Kris Mayes emphasized the state's vulnerability to extreme heat and other climate-related issues, stating that rescinding the Endangerment Finding would only exacerbate these conditions.

“On the day we file this lawsuit, much of Arizona is under an extreme heat warning due to an unprecedented early heat wave,” Mayes remarked. “The decision by the Trump administration to rescind the Endangerment Finding will only accelerate climate change.” This statement highlights the urgency with which Arizona officials view the situation, noting that hundreds of residents die each year due to heat exposure exacerbated by climate change.

The coalition, which includes the attorneys general from states like California, New York, and Massachusetts, argues that the EPA’s rollback disregards decades of scientific research indicating the severity of climate change. They assert that the Trump administration's actions prioritize the interests of the fossil fuel industry over public health and environmental protection.

California Attorney General Rob Bonta, co-leading the lawsuit, stated, "The science doesn't lie. Climate change and GHG emissions are harming public health and causing devastating and ever-worsening disasters." He called the EPA's actions a failure to protect the health and welfare of Americans, especially vulnerable communities facing the brunt of climate impacts.

The Endangerment Finding, a result of the landmark 2007 Supreme Court case *Massachusetts v. EPA*, established that greenhouse gases are air pollutants under the Clean Air Act, thus giving the EPA the authority to regulate them. The Trump administration's recent actions, however, have sought to undermine this legal framework, claiming that the agency lacks the authority to impose stringent greenhouse gas regulations.

Critics have labeled this move as reckless, pointing out that Arizona, in particular, has been experiencing record heat and severe climate-related challenges. For instance, the summer of 2025 saw Phoenix record 113 consecutive days of triple-digit temperatures, contributing to a significant number of heat-related deaths.

Arizona’s environmental advocates have voiced their concerns, stating that the rollback of climate regulations will disproportionately affect communities already facing environmental injustices. Pita Juarez from Moms Clean Air Force condemned the EPA's decision as an "unprecedented attack on public health protections," warning that future generations will bear the consequences.

The lawsuit comes amidst broader national concerns regarding climate change and public health. The coalition aims to reinstate the Endangerment Finding and restore regulatory standards for greenhouse gas emissions, which are critical for mitigating climate change impacts. The EPA’s rollback is seen as a direct threat to these efforts and to the health of millions of Americans.

As Arizona and its allies prepare for a legal battle, the outcome could have far-reaching implications for environmental policy across the United States. The coalition believes that defending the Endangerment Finding is essential not only for climate action but also for safeguarding public health and environmental justice in affected communities.

In conclusion, Arizona's participation in this lawsuit marks a significant step in the fight against climate change, reflecting a growing consensus among states that federal action is necessary to protect the environment and public health from the adverse effects of climate change.

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