WASHINGTON (AP) — A coalition of health and environmental groups sued the Environmental Protection Agency on Wednesday, challenging the rescinding of a scientific finding that has been the central basis for U.S. action to regulate greenhouse gas emissions and fight climate change.

A rule finalized by the EPA last week revoked a 2009 government declaration known as the endangerment finding that determined that carbon dioxide and other greenhouse gases threaten public health and welfare. The Obama-era finding is the legal underpinning of nearly all climate regulations under the Clean Air Act for motor vehicles, power plants and other pollution sources that are heating the planet.

The repeal eliminates all greenhouse gas emissions standards for cars and trucks and could unleash a broader undoing of climate regulations on stationary sources such as power plants and oil and gas facilities, experts say.

The legal challenge, filed in the U.S. Court of Appeals for the District of Columbia Circuit, asserts that the EPA’s rescission of the endangerment finding is unlawful. The 2009 finding supported common sense safeguards to cut climate pollution, including from cars and trucks, the lawsuit says. Clean vehicle standards imposed by the Biden administration were set to “deliver the single biggest cut to U.S. carbon pollution in history, save lives and save Americans hard-earned money on gas,” the coalition said in filing the case.

After nearly two decades of scientific evidence supporting the 2009 finding, “the agency cannot credibly claim that the body of work is now incorrect,” said Brian Lynk, a senior attorney at the Environmental Law & Policy Center.

“This reckless and legally untenable decision creates immediate uncertainty for businesses, guarantees prolonged legal battles and undermines the stability of federal climate regulations,” Lynk said.

The Supreme Court ruled, in a landmark 2007 case, that carbon dioxide and other greenhouse gases are “air pollutants” under the Clean Air Act. Since the high court’s decision, in a case known as Massachusetts v. EPA, courts have uniformly rejected legal challenges to the endangerment finding, including a 2023 decision by the U.S. Court of Appeals for the District of Columbia Circuit.

The dispute is likely to end up back before the Supreme Court, which now is far more conservative than in 2007.

• Trump administration claims the finding ‘strangled’ business

The lawsuit was brought by groups including the American Public Health Association, American Lung Association, Alliance of Nurses for a Healthy Environment and Physicians for Social Responsibility, along with environmental groups such as the Center for Biological Diversity, Conservation Law Foundation, Environmental Defense Fund, Natural Resources Defense Council and Sierra Club.

The suit named EPA and its administrator Lee Zeldin as defendants.

President Donald Trump said in announcing the repeal that it was “the single largest deregulatory action in American history, by far,” while Zeldin called the endangerment finding “the Holy Grail of federal regulatory overreach.”

The endangerment finding “led to trillions of dollars in regulations that strangled entire sectors of the United States economy, including the American auto industry,” Zeldin said. “The Obama and Biden administrations used it to steamroll into existence a left-wing wish list of costly climate policies, electric vehicle mandates and other requirements that assaulted consumer choice and affordability.”

• finding spurred new climate regulations

Under the Clean Air Act, EPA is legally required to limit emissions of any air pollutant that causes or contributes to “air pollution that may reasonably be anticipated to endanger public health or welfare.”

In its 2007 ruling, the Supreme Court told EPA to determine, based on the science, if that pollution endangers human health and welfare. EPA made that determination in 2009, which led to new standards for vehicles. It built on that finding when issuing other standards.

EPA’s repeal of the endangerment finding, along with the elimination of safeguards to limit vehicle emissions, “marks a complete dereliction of the agency’s mission to protect people’s health and its legal obligations under the Clean Air Act,” said Gretchen Goldman, president and CEO at the Union of Concerned Scientists, which is part of the suit.