UCLA experts: EPA plans to revoke its own endangerment finding, weakening pollution protections

The Environmental Protection Agency plans to announce Thursday that it is revoking what is known as the endangerment finding, the scientific determination that greenhouse gases harm human health. EPA Administrator Lee Zeldin has called the move "the largest act of deregulation in the history of the United States."

The endangerment finding forms the basis for virtually all of the EPA regulations that curb carbon dioxide, methane and other greenhouse gases, including from the power sector, oil and gas facilities and from cars and trucks. The scientific evidence connecting greenhouse gas emissions and climate change is well-established, and in 2009 the EPA issued its finding that greenhouse gases endanger public health and welfare and required federal regulation of emissions and emissions reporting. Now that's up in the air.

UCLA experts are tracking this major development and its ramifications. Researchers can speak about the legal implications; the established link between greenhouse gases, climate change and extreme weather; the health harms from greenhouse gas air pollution; and more.

A silver lining: Increased state freedom to regulate gases

Carlson is the Shirley Shapiro Professor of Environmental Law as well as faculty director of the Emmett Institute on Climate Change and the Environment at UCLA School of Law. She has written about the potential repeal of the endangerment finding and its She previously served in the Biden administration as acting administrator of the National Highway Traffic Safety Administration. Her new book, "Smog and Sunshine: the Surprising Story of How Los Angeles Cleaned Up Its Air," will be released on April 7.

"Why repeal the endangerment finding at all? First, the Trump administration may be aiming to get the U.S. Supreme Court to overturn its landmark decision in Massachusetts v. EPA, which required the EPA in the first place to determine whether greenhouse gases - when emitted from vehicles - endanger public health and welfare. Second, repealing the endangerment finding allows EPA to avoid replacing all the Biden administration climate rules that were issued under the Clean Air Act after it rescinds them."

"There is a potential silver lining here. Upending the endangerment finding might also allow states to regulate greenhouse gases from cars and trucks. The Clean Air Act prohibits states from issuing vehicle standards for emissions that are subject to the act. California, of course, can regulate emissions but it needs EPA permission to do so. If greenhouse gases aren't subject to the Clean Air Act, there's an argument that states could then regulate them independently."

Email: [email protected]

"A dangerous attack on science and the rule of law"

Camacho is a professor at UCLA School of Law and serves on the board of directors for the Center for Progressive Reform. His new book, "Lessons for a Warming Planet: A Vital History of U.S. Environmental Law," will be released on April 21, 2026.

"When it was adopted 17 years ago, there was overwhelming scientific support for the endangerment finding, and the evidence since then has only mushroomed. Even Trump's NASA acknowledges that climate change is 'unequivocal,' and that human pollution is the primary cause. Major Supreme Court cases have upheld EPA's finding and many other EPA actions that rely on this finding. At a minimum, the decision to repeal the endangerment finding is a waste of public resources; at worst, it is a dangerous attack on science and the rule of law."

"The history of U.S. environmental law is a story of government wantonly facilitating destructive and wasteful resource exploitation that is eventually met and overcome by resistance. Prior generations saw a combination of visionary leaders, expressive social movements and careful political coalitions deploy legal imagination to advance mammoth legal and social change. I am confident that this generation has all of the qualities necessary to safeguard this planet for future generations in the same way."

Email: [email protected]

Less regulation means more air pollution

Zhu is an air quality researcher and professor of environmental health sciences at the UCLA Fielding School of Public Health and UCLA's Institute of the Environment and Sustainability. Her recent work focuses on the dangers posed by urban fire smoke, and how people can protect themselves from harmful pollutants during and after urban conflagrations.

She can speak to the harms that greenhouse gases and unregulated emissions pose to human health.

"Greenhouse gases and air pollutants are closely linked, often originating from the same sources. Rolling back the endangerment finding risks increasing air pollution exposures, particularly in vulnerable communities, with real consequences for respiratory, cardiovascular and overall population health."

Email: [email protected]

A threat to health and a "blow to global efforts"

Jerrett is an air quality researcher and the Jonathan Fielding Professor of Climate Change and Public Health at the UCLA Fielding School of Public Health, with expertise in the health effects of wildfire smoke. His works include a study on the death toll from wildfire smoke, showing that long-term impacts resulted in more than 50,000 deaths in California over a decade. He also has expertise in extreme heat effects and contributed to California's Fifth Climate Change Assessment.

He can speak to the harms that greenhouse gases and unregulated emissions pose to human health.

"Since the original endangerment finding in 2009, the scientific evidence linking climate change to numerous threats to public health like extreme heat, wildfires, infectious disease and severe storms that cause destructive flooding has gotten a lot stronger. This decision will increase the clear and present danger of climate change to the health and well-being of Americans now and in the future. It's also a blow to global efforts to confront the serious public health threats from climate change."

Email: [email protected]

Greenhouse gases contribute to climate change and threaten human health

Hall is a climate scientist and director of both the Sustainable LA Grand Challenge and Institute of the Environment and Sustainability. He can speak to the role that greenhouses gases play in climate change, the threat climate change poses to human health through extreme weather, and the vital role of collective action and government policies to slow climate change.

"The scientific evidence that greenhouse gases contribute to climate change and pose risks to human health is extensive and well established. As wildfire, extreme heat, flooding, and drought increasingly affect communities across the country, coordinating collective action to mitigate the root cause of these growing threats will be critical to protecting human thriving. Policies informed by rigorous research remain essential to protecting lives, livelihoods, and long-term economic stability."

Email: [email protected]

People bear the health harms from pollution

Dr. Eisenman is a UCLA Fielding School of Public Health professor of community health sciences, an associate professor of medicine at the David Geffen School of Medicine at UCLA, co-director of the Fielding School's Center for Healthy Climate Solutions and director of the Center for Public Health and Disasters.

He can speak to the harms that greenhouse gases, unregulated emissions and resulting extreme heat pose to human health.

"Repealing the endangerment finding lets the fossil fuel industry off the hook and leaves our communities to bear the health harms of climate pollution. Whether it's more frequent and higher heat or it's the smoke from larger and more frequent wildfires, doctors must continue speaking out, because our patients cannot afford this harm."

Email: [email protected]

"Repealing a foundation of U.S. climate regulation"

Venkat is a medical anthropologist and an associate professor at UCLA's Institute for Society & Genetics, with joint appointments in both anthropology and history. He studies extreme heat and inequality, and is director of the UCLA Heat Lab.

"The EPA is repealing a foundation of U.S. climate regulation. The endangerment finding succeeded in formally connecting the dots between greenhouse gas emissions, climate change, extreme heat and human health - an effort over a century in the making. The endangerment finding identified climate change as an existential threat to the body, rather than a distant environmental worry. Court after court has upheld the endangerment finding, affirming not only the authority of the EPA under the Clean Air Act, but the underlying science itself."

Email: [email protected]

The risk of more extreme weather

McKinnon is an atmospheric scientist and statistician studying climate extremes and large-scale climate variability. She is an associate professor in the department of atmospheric and oceanic sciences, and statistics and data science. Her work seeks to improve our understanding and prediction of climate extremes, variability and change.

She can speak about the established role of greenhouse gases in causing climate change, and the impacts of climate change on high-impact weather extremes.

Email: [email protected]

Cities are not prepared

Turner, an expert on the effects of extreme heat, is an associate professor of urban planning at the UCLA Luskin School of Public Affairs and co-leader of the Heat Resilient L.A. project at UCLA. She studies and recommends policies to address urban heat impacts, from playgrounds to whole neighborhoods.

She can speak to the impact extreme heat from climate change has on human health, and the inability of cities' infrastructure and institutions to respond to extreme heat.

Email: [email protected]