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By Kate Yoder, Grist
In 2009, the Environmental Protection Agency declared that the rising concentrations of greenhouse gases in the atmosphere threatened public health and welfare. This “endangerment finding,” as it’s known in legal jargon, may have sounded self-evident to those who had been following climate science for decades, but its consequences for U.S. policy were tremendous: It allowed the EPA to issue rules limiting emissions from U.S. vehicles, power plants and other industrial sources. While those rules have not always survived court challenges and changing presidential administrations, the regulatory authority underpinning them has proven remarkably stable.
On Tuesday, President Donald Trump’s EPA took a major step toward changing that. At a truck dealership in Indianapolis, EPA Administrator Lee Zeldin announced a formal proposal to repeal the endangerment finding, which has been in the works since the beginning of Trump’s second presidency. At the same time, Zeldin announced a plan to repeal all federal greenhouse gas emissions regulations for motor vehicles. “If finalized, today’s announcement would amount to the largest deregulatory action in the history of the United States,” he said at the press conference.
Zeldin accused his predecessors at the EPA of making “many, many, many mental leaps” in the 2009 declaration, and he argued that the “real threat” to people’s livelihoods is not carbon dioxide but instead the regulations themselves, which he claimed lead to higher prices and restrict people’s choices.
If the EPA succeeds in reversing the endangerment finding, it would “eviscerate the biggest regulatory tool the federal government has” to keep climate change in check, said Ann Carlson, an environmental law professor at the University of California, Los Angeles.
Republicans in Congress have already repealed much of former President Joe Biden’s landmark climate law, which aimed to put the U.S. within reach of its Paris Agreement targets primarily by funneling money to renewable energy sources. Rescinding the endangerment finding targets the other main tool the U.S. government can use to address climate change: the executive branch’s power to limit emissions through regulatory action. In other words, Republicans have already eliminated many of the federal government’s proverbial climate carrots — now they’re going after the sticks.
“We will not have a serious national climate policy if this goes through,” said Patrick Parenteau, an emeritus professor of climate policy and environmental law at Vermont Law School.
But that’s a big “if.” Experts say that the EPA’s plan is bound to be embroiled in years of lawsuits, perhaps one day making its way to the Supreme Court, which blessed the EPA’s authority to regulate greenhouse gases in 2007 and declined to hear a challenge to the endangerment finding as recently as December 2023. And even if the EPA does manage to overturn the endangerment finding after all court challenges have been exhausted, it would result in sweeping consequences — including some that the administration’s allies in the oil industry may not like. Indeed, the risk is serious enough that some fossil fuel industry groups have urged the Trump administration not to repeal the finding.
The tussle over the endangerment finding stems from differing interpretations of the Clean Air Act. When Congress expanded the law in 1970, it tasked the EPA with regulating air pollutants that threaten public health, but it kept the definition of “pollutant” broad. “They had the foresight to understand that they could not foresee every potential air pollutant that would endanger public health and welfare in the many decades to come,” said Zealan Hoover, who was a senior adviser to the EPA under Biden. That gave the EPA some leeway to determine exactly what it should be regulating — a question that presidents have approached very differently, with Democrats typically trying to expand the agency’s power and Republicans trying to limit it. With its 2009 endangerment finding, the Obama administration added carbon dioxide and five other greenhouse gases to the list.
Now that Zeldin has announced a plan to strike down the finding, the EPA will open a 45-day period for the public to weigh in on the proposal. The agency is supposed to take that feedback into account before moving to finalize the rule. At that point, states and environmental groups may sue the EPA in what’s expected to be a yearslong court battle.
“The lawyering that’s going to go on is going to make a lot of people rich,” Parenteau said. In the meantime, Zeldin would likely work to undo existing regulations on greenhouse gas emissions, unless the courts were convinced to pause the implementation of the new rule.
Any lawsuit would probably end up in the D.C. Circuit Court of Appeals, which hears cases concerning federal policymaking. Law experts say the EPA’s argument may not fare well with those judges, as the circuit has upheld the EPA’s authority to regulate greenhouse gases under the Clean Air Act in the past. On top of that, when Congress passed the Inflation Reduction Act in 2022, Democrats amended the Clean Air Act to explicitly declare carbon dioxide and greenhouse gases as air pollutants, bolstering the foundation for regulating them. Republicans did not repeal that language when they gutted much of the rest of the Biden-era law, and challengers are likely to invoke those amendments in court, Carlson said.
But that wouldn’t necessarily be the end of it, because such a case might go all the way to the Supreme Court. The court’s conservative majority could then choose to undermine Massachusetts v. EPA, the 2007 decision that gave the EPA authority to regulate greenhouse gas emissions and led to the endangerment finding. “That may be the ultimate aim here,” Carlson said, “to get the Supreme Court to revisit Massachusetts v. EPA to make it basically impossible to regulate greenhouse gases under the Clean Air Act.”
Undoing the finding wouldn’t just dismantle the foundation of U.S. climate regulation — it might also weaken oil companies’ best legal defense in the flood of climate lawsuits brought against them by cities and states. For years, oil companies have relied on a different Supreme Court ruling to argue that federal law shields them from state lawsuits over climate change. In the 2011 ruling American Electric Power Co. v. Connecticut, the Supreme Court found that because the EPA was already regulating greenhouse gases under the Clean Air Act, states couldn’t separately sue polluters under federal “nuisance” law — a type of legal claim used when someone’s actions interfere with public rights, such as the right to a healthy environment.
The court’s reasoning was that Congress had delegated the task of regulating emissions to the EPA, leaving no room for federal courts to step in on making climate policy. But if the endangerment finding is revoked, and the EPA no longer regulates those emissions, that argument could fall apart, leaving fossil fuel companies vulnerable in courts across the country.
“There is great concern that reversing the finding would open the door to a lot more nuisance lawsuits against all types of energy companies,” Jeff Holmstead, a partner with energy law firm Bracewell, told E&E News earlier this year. The oil industry may then pursue a backup plan: Companies could ask Congress, which is currently controlled by a narrow Republican majority, to grant them legal protection from climate lawsuits, according to Parenteau.
Undoing the endangerment finding could leave fossil fuel companies navigating a patchwork of state laws instead of a single cohesive federal policy. If greenhouse gas emissions are no longer regulated under the Clean Air Act, states would presumably be free to make their own rules, Carlson added. Among other consequences, that could strengthen California’s case against the Trump administration over its right to place stricter-than-federal standards on vehicle emissions. “There’s potential for a lot of chaos,” she said.
It’s possible that a more liberal presidential administration could one day reinstate the endangerment finding, even if Zeldin manages to revoke it. But it would be a while before that could translate to any meaningful action on climate change, according to Hoover.
“Unfortunately, for anyone who wants to see government solve a big problem, there’s very little you can achieve through regulations in four years,” he said.
This article originally appeared in Grist at https://grist.org/politics/epa-endangerment-finding-zeldin-announcement/. Grist is a nonprofit, independent media organization dedicated to telling stories of climate solutions and a just future. Learn more at Grist.org.
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