Climate groups file lawsuit against repeal of endangerment finding, augering a legal showdown

A coalition of 17 environmental and health organizations filed a lawsuit Wednesday challenging the EPA’s decision to repeal a 2009 finding that concluded that greenhouse gas emissions are harmful to human health and fall under the EPA’s jurisdiction to regulate them. 

The finding impacts a variety of emission sources, but the repeal only impacts the part of the regulations dealing with mobile sources, namely motor vehicles. Lawsuits challenging the repeal were expected, and the question now is whether the repeal will survive in court. 

Questions about the Clean Air Act

Prior to the final rule being published, Steve Milloy, senior legal fellow with the Energy and Environmental Legal Institute and publisher of “JunkScience.com,” told Just the News that, if the repeal is going to have any staying power, the Supreme Court will need to overturn Massachusetts v. EPA, a 2007 decision that opened the door for the process by which the Obama administration finalized the original rule. 

In that ruling, the Supreme Court decided that greenhouse gas emissions fit the Clean Air Act’s definition of an “air pollutant.” As a result, the EPA is required to determine if emissions endanger public health and the welfare of the public, or if the science is too uncertain to make such a determination. 

Emails obtained through Freedom of Information Act (FOIA) requests showed that the Obama administration's EPA had approached the question with a pre-determined conclusion that these emissions are a threat to human health and the agency needed to regulate them. 

In its final rule issued last week, the EPA argues that the relevant section of the Clean Air Act doesn’t authorize the agency to set emission standards in response to global climate change concerns. So the endangerment finding and resulting regulations have no legal basis. Due to the sweeping economic and policy consequences of the finding, the rule explains, the decision lies solely with Congress.

Revisiting Massachusetts v. EPA

The 17 health and environmental organizations filed their petition in the Washington, D.C., appellate court, asking the court to review the EPA’s repeal. In a statement, Earthjustice, one of the petitioners, argues that the Trump EPA is revisiting arguments that the Supreme Court already considered and rejected in Massachusetts v. EPA.

However, the final rule points out that Supreme Court decisions since Massachusetts v. EPA aren’t aligned with its reasoning. In 2022, the high court ruled in West Virginia v. EPA that Congress had not granted the EPA the authority to place emission caps on power plants as a means to regulate how Americans generate electricity, and in June 2024, the high court struck the “Chevron deference,” which allowed federal agencies broad latitude in interpreting laws when Congress hasn’t provided specific guidelines.

In his dissent in Massachusetts, Justice Antonin Scalia said, “It follows that everything airborne, from Frisbees to flatulence, qualifies as an ‘air pollutant.’ This reading of the statute defies common sense.”

To clarify or overturn Massachusetts 

Chris Horner, an environment and energy policy attorney, said the EPA is giving the Supreme Court two options to address the mistake made in Massachusetts v. EPA. Either the court has to clarify the decision or overturn it. 

Horner says that the court ruled in Michigan v. EPA that the EPA erred in not considering costs to power-plant emissions, which provided more clarity. And in overturning the “Chevron deference” in 2024, it limited agency regulations to specific authority granted by Congress, which is a reason to overturn Massachusetts.

“Any reading of the Clean Air Act to require or even permit all-pain-no-gain policies — of which the Endangerment Finding is the epitome — is unlawful,” Horner said. 

The EPA is setting up the prospect of reversing Massachusetts by concluding that the endangerment finding was a mistake on the EPA’s part, as opposed to a rebellion against the court’s mistake in the ruling. This approach, Horner said, seeks a clarification, but is really seeking reconsideration and an opportunity to overturn the ruling. 

Questions about Congressional intent

Kenny Stein, vice-president of policy for the Institute for Energy Research, told Just the News that the groups opposing the repeal of the endangerment finding haven’t updated their arguments since Massachusetts, and that’s reflected in the Earthjustice statement, which he says doesn’t mention subsequent Supreme Court rulings. 

Massachusetts rests upon the conclusion that the Clean Air Act grants the EPA authority over greenhouse gas emissions if the agency determines them to be a threat to human health. However, Stein points out, Congress has passed legislation regarding specific greenhouse gasses, including methane and hydrofluorocarbons. 

“That actually strengthens the argument that the Clean Air Act generally does not apply to greenhouse gasses, because if it generally applied, then there'd be no reason to pass these separate laws,” Stein said. 

Dr. Roger Pielke Jr., senior fellow at the American Enterprise Institute, argues in his “The Honest Broker” Substack that the 2009 endangerment finding has a potential legal vulnerability with how it regards water vapor, which is also a greenhouse gas that can have significant impacts on local and regional climate. 

However, the 2009 EPA determined it has a “negligible contribution to climate change.” The problem is that Massachusetts rejected the argument that emissions from vehicles are too small to have a discernible impact on climate and therefore not worthy of regulation.

Pielke wrote that regulation of water vapor would be a “huge policy and political mess, imposing enormous costs,” which would be neither “feasible, nor would it make any policy sense.” 

The final rule issued last week argues that, under the logic of the 2009 endangerment finding, water vapor should have been included as a greenhouse gas the agency needed to regulate. “The logic of regulating water vapor appears absurd, but it is the same logic required to regulate GHGs under” the relevant sections of the Clean Air Act, the final rule states. 

Now the courts will decide

Stein said the Trump administration will almost certainly lose in the D.C. Circuit. How it fares in the Supreme Court is far less certain, but the problem is that it could take years to get there. Voters in 2028 could decide to elect a Democrat president, and should he or she overturn the repeal of the endangerment finding, the lawsuits will be withdrawn until another administration gives a reason to restart the process. 

“There's a lot of uncertainty that goes into that, and just given the speed at which courts move, it's highly unlikely that you will get a Supreme Court decision before there's a new president,” Stein said. 

Milloy from the Energy and Environmental Legal Institute told Just the News there are reasons to wonder if the Trump administration will effectively argue the case. He points to the courts shooting down the administration’s pause on offshore wind projects under construction due to concerns over how they impact radar. 

“There’s some incompetent lawyering going on, and we can’t afford to lose this,” Milloy said. 

For his part, Pielke wrote that he’s not convinced it would be struck down. Rather than leaving it to the executive and judicial branches to figure out, the best resolution to the debate, Pielke argued, is for Congress to clarify if the Clean Air Act grants the EPA the authority to regulate greenhouse gas emissions. 

Short of that, it will be up for the courts to decide, and where that ends up is anybody's guess.