climate change is at the center of a new legal fight after a coalition of states and local governments sued the Trump administration over the Environmental Protection Agency’s decision to revoke a landmark 2009 scientific determination. The case was filed Thursday in the US Court of Appeals for the District of Columbia Circuit, with Massachusetts, California, New York, and Connecticut leading the challenge. The lawsuit argues the EPA’s February rescission of the “endangerment finding” was illegal, and it seeks to restore the legal foundation for major federal emissions standards.
What the lawsuit is challenging
The lawsuit targets the EPA’s February action rescinding the 2009 endangerment finding, a determination that greenhouse gases threaten public health and welfare and that underpins federal climate standards for cars, power plants, and other sources of greenhouse gas pollution. The coalition includes 24 states and a dozen cities and counties, and it is asking the court to reinstate the finding and to reverse a related EPA move aimed at repealing all limits on standards for planet-warming emissions from motor vehicles.
The White House has described the rescission as the “single largest deregulatory action in US history, ” a characterization cited in the legal challenge. The case also comes as the court may consolidate it with a separate lawsuit filed by environmental groups in February.
Immediate reactions from officials and experts
Andrea Joy Campbell, Massachusetts Attorney General, framed the lawsuit as a response to what the coalition sees as a break from legal and scientific obligations. “When the federal government abandons the law and the science, everyday people suffer the consequences, ” Campbell said.
Letitia James, New York Attorney General, said communities are already being hit by climate disasters and tied the policy rollback directly to a weakening of federal protections tied to climate change. “Across our country, communities are already suffering from climate disasters. From freak storms to devastating floods to deadly cold snaps and unbearable heat waves, the climate crisis is here, and it is already reshaping the way we live, ” James said. She added: “Instead of helping Americans face our new reality, the Trump administration has chosen denial, repealing critical protections that are foundational to the federal government’s response to climate change. ”
From the medical community, Anna Goldman, Primary Care Physician and Medical Director of Climate and Sustainability at Boston Medical Center, warned of direct public health impacts from weakening the regulatory framework. “As a physician, I see the consequences of climate change and air pollution first-hand: growing numbers of hospitalizations during summer heat waves, asthma attacks triggered by wildfire smoke, and patients uprooted by floods and hurricanes, ” Goldman said. She called the EPA’s move “a direct threat to the health of all Americans, ” saying it would “directly cause disease and premature death across our country. ”
An EPA spokesperson defended the agency’s action, saying it “carefully considered and re-evaluated” the endangerment finding, the 1970 Clean Air Act, and later legal decisions, concluding the agency does not have “statutory authority to prescribe motor vehicle emission standards” for the purpose of addressing global climate change concerns. The EPA has also argued that the Clean Air Act is meant to regulate pollution that harms health or the environment through local and regional exposure, and that it does not apply to carbon dioxide and other planet-warming pollutants.
Quick context on why the 2009 finding matters
The endangerment finding determined that carbon dioxide and other greenhouse gases pose a threat to public health and welfare, establishing a legal basis for federal rules that aim to lower emissions from major sources. Its rescission is now being challenged by states, local governments, and separate plaintiffs from environmental and health advocacy groups.
What’s next in court
The case is now before the US Court of Appeals for the District of Columbia Circuit, with the coalition seeking to reinstate the endangerment finding and unwind related moves affecting vehicle emissions standards. The court may consolidate this case with a February lawsuit filed by environmental groups, a step that could shape the timeline and scope of arguments.
As this proceeds, the key question is whether the court agrees that the rescission violated legal requirements tied to the Clean Air Act framework and whether the 2009 determination remains the federal government’s bedrock tool for regulating greenhouse gases. For now, the states say the stakes are immediate and practical: protections they view as foundational to responding to climate change are being fought over in federal court, and the next major developments will come through court scheduling and any consolidation decisions.
