President Trump Ignores Climate Science, but the Law Will Hold Him Accountable: California Files Lawsuit Challenging EPA’s Rescission of Endangerment Finding

Representing California in the multistate lawsuit, Attorney General Bonta, Governor Newsom, and CARB are joined by the City of Los Angeles, the City and County of San Francisco, and the County of Santa Clara

SACRAMENTO -In response to President Donald Trump's illegal attempt to overrule science and abandon an entire category of federal climate protections, California Attorney General Rob Bonta, alongside California Governor Gavin Newsom and the California Air Resources Board (CARB), today co-led a coalition of 25 attorneys general, the Governor of Pennsylvania,10 cities and counties in filing a petition challenging the U.S. Environmental Protection Agency's (EPA) rescission of the Endangerment Finding in the U.S. Court of Appeals for the D.C. Circuit. The Endangerment Finding is EPA's formal acknowledgement that greenhouse gas emissions from motor vehicles contribute to air pollution that drives climate change and endangers public health and welfare; it has served as the legal basis under the Clean Air Act for limiting climate pollution from vehicles.

In comments previously submitted to EPA, the coalition argued that EPA's rescission of the 2009 finding violates settled law, clear Supreme Court precedent, and the longstanding, robust scientific consensus regarding the harmful impact of greenhouse gases from vehicle emissions on human health and welfare. The Trump Administration's decision to finalize its rescission will endanger hundreds of millions of Americans - particularly communities disproportionately burdened by environmental harms. The Endangerment Finding rescission will cause unprecedented disruption to the regulatory landscape and result in significant increases in the emission of greenhouse gases, with catastrophic consequences for residents, industries, natural resources, and public investments. In the lawsuit, California and the coalition ask the Court to vacate EPA's illegal rescission of the Endangerment Finding and restore EPA's greenhouse gas emission standards for vehicles, which three prior administrations - including the first Trump Administration - implemented and enforced.

"With the unlawful rescission of the Endangerment Finding, President Trump and his EPA have abandoned their most important mission: protecting the health and welfare of the American people. The science doesn't lie. Climate change and GHG emissions are harming public health and causing devastating and ever-worsening disasters. Our communities have felt the impact of destructive wildfires, watched families run from burning homes, inhaling toxic fumes, and we've seen entire communities wash away in severe floods. The President can't keep his head in the sand - climate change is real and decades of settled science warned us this was coming," said Attorney General Rob Bonta. "Let me be clear: This unlawful rescission is not about cutting 'red tape.' The president is choosing Big Oil profits over our health, and betting that the American people won't notice the cost until the bill comes due at the expense of our communities. We will not stand idly by while the federal government abdicates its responsibility to protect the public and follow the law. California will vigorously defend the Endangerment Finding in court and continue to fight to protect our communities, our health, and our natural resources."

"This is what corruption looks like. Donald Trump is breaking the laws that protect Americans from climate pollution - all to enrich his Big Oil and his wealthy polluting allies," said Governor Gavin Newsom. "Workers, families, and communities would pay the price, left choking on dirty air. No one is above the law in this country. Not even the president. We'll fight this lawlessness in court."

"The Trump Administration is failing to protect everyday people across this country in countless ways, including through their unlawful attempts to unwind decades of science-based policy," said Yana Garcia, Secretary for Environmental Protection. "The truth is that climate change presents immediate threats to human health and to our environment, and rising temperatures threaten the welfare of American families by increasing household costs across this country every day. California remains committed to climate action and will keep fighting back because our people and our future deserve better."

"The Trump Administration, in recklessly repealing the Endangerment Finding, is abdicating their responsibility to protect American lives," said CARB Chair Lauren Sanchez. "California isn't going to sit back and watch while the federal government dismantles critical public health protections - we're going to fight back."

"Federal air quality regulations are critical to protecting human health from the impacts of climate change," said Dr. Rita Nguyen, California's Assistant Health Officer. "Climate change is a serious threat to human health as California experiences more frequent, more severe, and longer-lasting episodes of extreme heat. For instance, during the September 2022 record-breaking 10-day heat wave in California, there was a 5 percent increase in deaths - 395 more deaths than would be expected. Additionally, climate-related hazards like heat, wildfires, extreme weather, and poor air quality can disproportionately harm the mental health and well-being of children and youth, contributing to anxiety, depression, post-traumatic stress disorder, decreases in learning, and other challenges that can have long-term consequences."

"We're proud to stand with Attorney General Bonta and partners across California and the nation in defending science and protecting the health and safety of our communities," said Santa Clara County Counsel Tony LoPresti. "At a time when federal actions threaten decades of progress, it is critical that state and local governments work together to push back and uphold strong, science-based standards. We won't let unlawful federal actions put our communities, health, and economy at risk."

"Climate change is an existential threat to humanity," saidSan Francisco City Attorney David Chiu. "Rolling back the Endangerment Finding means fewer safeguards against the pollution that drives climate change and worsens air quality. This reckless and illegal move disregards decades of scientific evidence and harms communities already on the front lines of the climate crisis."

Under the federal Clean Air Act, EPA is required to regulate pollutants from vehicles that cause or contribute to dangerous air pollution. The 2009 Endangerment Finding was the direct result of the landmark 2007 Supreme Court decision in Massachusetts v. EPA, which confirmed that greenhouse gases are an air pollutant under the Clean Air Act. In response to that opinion, and after years of detailed scientific review, EPA acknowledged 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.

In its proposal to rescind the Endangerment Finding, issued last summer, EPA claimed that an updated review of climate science "cast significant doubt " on the Endangerment Finding, based on a report by the Department of Energy's "Climate Working Group" - a quintet of climate change contrarians hand-picked by the Secretary of Energy to dispute the scientific consensus. That group was quickly disbanded in the face of legal challenges and never released a final report. Their draft report, circulated last July and cited throughout EPA's proposal, was met with an outpouring of criticism from scientists. And the group violated federal law so profoundly that even the Trump administration was "not contesting" the merits of legal challenges. Consistent with the administration's failed attempt to contort science, it continues to seek to overrule decades of scientific consensus on climate change. Last month, EPA repealed the Endangerment Finding and eliminated all existing and future federal greenhouse gas standards for vehicles.

This federal rescission will cause an unprecedented disruption to 15 years of regulatory progress. As the nation's largest source of greenhouse gas emissions, the transportation sector will see increasing climate-destabilizing pollution, while American investment in future technologies, new factories, and jobs will decline, undermining U.S. leadership in this sector as well as in addressing climate change.

In the lawsuit, California and the coalition allege that EPA's rescission of the Endangerment Finding violates the Clean Air Act as well as the Administrative Procedure Act. Specifically, the coalition highlights that EPA's rescission rests on the flawed assertion - soundly rejected by the Supreme Court - that it lacks legal authority to regulate greenhouse gas emissions and ignores overwhelming and longstanding scientific evidence that greenhouse gases endanger public health and welfare. The coalition also argues that the rule's elimination of all existing and future federal greenhouse gas emission standards for vehicles violates the agency's legal obligations and its fundamental responsibility to protect public health and welfare from environmental harm.

In August 2025, following the Trump Administration's initial proposal to rescind the Endangerment Finding, Attorney General Bonta testified before the EPA, highlighting the illegality of the proposed rescission and the agency's reliance on flawed and unscientific sources to deny climate change. In the fall of 2025, he co-led a coalition of 23 attorneys general and seven counties and cities in submitting two comment letters, urging the EPA to abandon this illegal proposal.

Attorney General Bonta co-leads the lawsuit alongside the attorneys general of Massachusetts, New York and Connecticut. They are 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.