Press Release  AG Campbell Challenges Unlawful Rescission of Landmark 2009 Greenhouse Gas Endangerment Finding

BOSTON — Massachusetts Attorney General Andrea Joy Campbell today led a coalition of 24 states, the District of Columbia, the U.S. Virgin Islands, and 12 cities and counties to challenge the U.S. Environmental Protection Agency’s (EPA) unlawful attempt to rescind its 2009 Endangerment Finding – the agency’s seminal determination that greenhouse gas pollution from motor vehicles drives climate change and endangers public health and welfare. 

“Climate change is real, and it’s already affecting our residents and our economy,” said AG Campbell. “When the federal government abandons the law and the science, everyday people suffer the consequences. As a mom, I want my boys – and every child in our state – to grow up breathing clean air and playing safely outdoors. Massachusetts has long led the way in protecting our communities from the dangers of greenhouse gas emissions and we are proud to stand up once again to lead this fight for our future.”

The 2009 Endangerment Finding was the direct result of the landmark 2007 Supreme Court decision in Massachusetts v. EPA, which confirmed that the Clean Air Act authorizes EPA to regulate greenhouse gas emissions that endanger public health and welfare. Based on years of rigorous scientific analysis and review, EPA in 2009 determined that emissions from motor vehicles contribute to air pollution that harms public health and welfare. EPA then set federal standards have led to significant reductions in motor vehicle greenhouse gas emissions.

Now, almost two decades later, EPA has rushed a rulemaking process to rescind the Endangerment Finding and repeal all motor vehicle greenhouse gas standards, blatantly disregarding the law and science. EPA’s rescission is based on flawed interpretations of the law — previously rejected by the Supreme Court — that the agency lacks authority to regulate greenhouse gas emissions. The rescission also ignores decades of peer-reviewed scientific evidence confirming the reality and severity of climate change. By eliminating all existing and future federal motor vehicle greenhouse gas emission standards, the rule violates EPA’s legal obligations, fundamental principles of administrative law, and the agency’s mission to protect public health and welfare.

Climate Change Threats Intensify Across Massachusetts

The effects of climate change are already being felt across the Commonwealth — from threats to public health to increased strain on critical infrastructure. Since 1900, statewide temperatures have risen nearly 3.5°F and are projected to continue climbing, bringing more extreme heat days each year and up to 400 additional heat-related deaths annually by the end of the century. If greenhouse gas emissions are not curbed, impacts across the state are projected to intensify.

Rising heat is straining the state’s infrastructure, including the electricity grid and commuter rail and subway lines, with annual rail repair costs projected to increase to $6 million by 2050 and $35 million by 2100. Intensifying storms are causing hundreds of millions in damages, with statewide flood costs projected to grow by $9.3 million annually by 2030.

Coastal communities are particularly at risk from intensifying climate change. More than 24,000 acres of wetlands in the Commonwealth could disappear by 2100, eliminating natural storm buffers and critical habitats. Rising seas threaten an estimated three million residents, with direct flood damage to commercial structures potentially reaching $270 million annually by 2090 and losses to state-owned coastal property exceeding $52 million per year by 2070.

Climate change impacts also worsen public health crises. Degrading air quality fuels Massachusetts’s pediatric asthma epidemic currently ranked third-worst in the nation, with rates projected to increase more than sevenfold in 2090, disproportionately affecting low-income communities and communities of color.

Today’s lawsuit is the latest action taken by AG Campbell and the coalition in their ongoing effort to fight back against EPA’s unlawful rescission of the 2009 Endangerment Finding. In August 2025, following the Trump Administration’s proposal to repeal the Endangerment Finding, AG Campbell testified before 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. In the fall of 2025, she co-led a coalition of 23 attorneys general and seven cities and counties in submitting two comment letters urging EPA to abandon the proposal, arguing that it would violate settled law, clear Supreme Court precedent, and scientific consensus, endanger hundreds of millions of Americans—particularly communities disproportionately burdened by environmental harms—and cause unprecedented disruption to the regulatory landscape with catastrophic consequences for residents, industries, natural resources, and public investments.  

AG Campbell is joined in filing this lawsuit, which she co-led with the attorneys general of California, Connecticut, and New York, by the attorneys general of: Arizona, Colorado, Delaware, Hawai‘i, Illinois, Maine, Maryland, Michigan, Minnesota, Nevada, New Jersey, New Mexico, North Carolina, Oregon, Rhode Island, Vermont, the Commonwealth of Virginia, Washington, Wisconsin, the District of Columbia; and the United States Virgin Islands, as well as Josh Shapiro, in his official capacity as Governor of the Commonwealth of Pennsylvania; the Cities of Albuquerque, New Mexico; Boston, Massachusetts; Chicago, Illinois; Cleveland, Ohio; Columbus, Ohio; Los Angeles, California; and New York, New York; the Counties of Harris, Texas; Martin Luther King, Jr., Washington; and Santa Clara, California; and the Cities and Counties of Denver, Colorado, and San Francisco, California. 

This matter is being handled by Deputy Bureau Chief Turner Smith, Assistant Attorney General for Climate Change Julia Jonas-Day, Special Assistant Attorneys General Luca Greco and Hannah Perls, Assistant Attorneys General Nathaniel Haviland-Markowitz and Meghan Davoren, and Paralegal Kate Mason, all of AG Campbell’s Energy and Environment Bureau.

Statements of Support

Michelle Wu, Mayor of Boston: 

“Attempting to erase the scientific consensus on greenhouse gas pollution puts our communities and our future at risk. Boston will continue to lead, protect public health, and hold the federal government accountable to the law as we work to reduce emissions and build a safer, more resilient city.”

Dr. Anna Goldman, Primary Care Physician, Medical Director of Climate & Sustainability, Boston Medical Center: 

“As a physician, I see the consequences of climate change and air pollution firsthand: growing numbers of hospitalizations during summer heat waves, asthma attacks triggered by wildfire smoke, and patients uprooted by floods and hurricanes. The EPA's rescission of the Endangerment Finding poses a direct threat to the health of all Americans. Rather than shielding our communities from the harms of air pollution and climate change, this action will directly cause disease and premature death across our country.”

Rocío Sáenz, Secretary Treasurer, Service Employees International Union (SEIU):

“As extreme heat, floods, wildfires, and hurricanes continue to intensify, working people are the ones paying the price with higher bills and worsening health. That's why SEIU is challenging the rollback of the Endangerment Finding on behalf of our members, and why we are proud to support this coalition of state and local governments that are fighting to protect our communities.”

John Walkey, Director of Climate Justice & Waterfront Initiatives, GreenRoots:

“GreenRoots denounces in the strongest terms the Trump Regime’s latest affront to science, justice and common sense in its rescission of the EPA's 2009 finding that pollutants from developing and burning fossil fuels, such as methane and carbon dioxide, can be regulated under the Clean Air Act. Our community lives with the reality of the impacts of burning fossil fuels from poor air quality to increased heat in the summer, to more frequent street flooding from climate change-strengthened storms, to rising sea levels. While we have fought long and hard to establish environmental protections for our community, this blatantly corrupt administration wouldn't just remove those protections but actively work to advance the opposite of what so many have tried to achieve - namely, environmental justice. The multistate legal challenge being brought forth by the Massachusetts AGO in partnership with many others is critical for communities like Chelsea and East Boston which bear the brunt of the effects of greenhouse gas pollution.”

Kate Sinding Daly, Senior Vice President for Law and Policy, Conservation Law Foundation:

“We applaud Attorney General Campbell and her colleagues for challenging the unlawful repeal of the endangerment finding, dismantling this bedrock scientific determination undermines critical efforts to curb deadly pollution and safeguard public health and welfare. We will stand shoulder to shoulder with the attorneys general in court to oppose this rollback and ensure federal agencies remain accountable and that families are not left to face the consequences of unchecked climate-warming pollution.”

Amy Boyd Rabin, Vice President of Policy & Regulatory Affairs, Environmental League of Massachusetts:

“Eliminating the Endangerment Finding undermines critical environmental safeguards and disregards decades of scientific evidence. Massachusetts remains on the frontlines defending the landmark ruling of MA v. EPA from 2007. ELM is proud to support the lawsuit filed by Attorney General Campbell, alongside leaders across the US, to challenge the EPA’s unlawful rollback of protections that safeguard public health. Our communities and climate are at risk, and we will continue fighting to hold the federal government accountable.” 

Patrick Herron, Executive Director, Mystic River Watershed Association:

“The rescission of this finding is a direct threat to the health of our rivers and the safety of the residents who live along them. In the Mystic River watershed, we are already seeing how climate change intensifies flooding, overwhelms our aging infrastructure, and drives up the municipal costs of managing and protecting our cities. To ignore the science of greenhouse gas endangerment is to abandon the communities most vulnerable to these impacts. We stand with Attorney General Campbell in this challenge because climate protection is not optional—it is a fundamental necessity for building resilient, healthy, and economically viable communities.”

Jennifer Zimmer, Co-Executive Director, Mothers Out Front:

“Caregivers don't need a federal finding to know that greenhouse gas pollution is putting our children in danger, but we need the legal protections it provides. Rescinding the Endangerment Finding and repealing motor vehicle emission standards doesn't change that reality; it just removes the guardrails meant to protect our kids. Mothers Out Front stands with Attorney General Campbell and this coalition because our children's health is not up for political negotiation.”

Sam Sankar, Senior Vice President of Programs, Earthjustice:

“We are grateful that Massachusetts and the 23other states, the District of Columbia, the U.S. Virgin Islands, and many local governments are suing to defend the endangerment finding to hold this administration accountable. Climate change is hurting their residents, straining their infrastructure, and shrinking their coasts. By trying to eliminate federal climate regulations in this moment, Trump’s EPA is disregarding the science and the law and is putting the American people in harm’s way.”

Alice Henderson, Senior Director and Lead Counsel for Transportation and Clean Air, Environmental Defense Fund:

“Environmental Defense Fund stands with state leaders in enforcing our nation’s clean air laws to protect communities from dirtier air, higher fuel costs, and climate-change driven disasters.  The endangerment finding is a fundamental pillar of U.S. climate policy and we will vigorously defend it in court alongside city, state, and business leaders.” 

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