Inside EPA's backdoor bid to stop regulating climate pollution

E&E News

30-05-2025

EPA is expected to soon argue that the U.S. power sector doesn't contribute 'significantly' to climate change — a bid that could give the agency cover to not regulate planet-warming emissions from a wide range of sources.
EPA included the argument in its draft repeal of Biden-era rules to limit pollution from power plants, according to two people briefed by EPA personnel and granted anonymity to discuss those conversations. The agency bolsters its argument by stating in the draft sent to the White House that U.S. fossil fuel power plants account for 3 percent of global emissions, The New York Times reported last week.
The assertion would take advantage of a section of the Clean Air Act that instructs the EPA administrator to decide whether a category of sources contributes enough harmful pollution to warrant regulation. That could offer a backdoor avenue for EPA to stop regulating most climate pollution — one where the agency has to clear a lower legal bar than overturning the so-called endangerment finding that underpins all Clean Air Act climate regulations.
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Industry attorneys who have expressed skepticism about the Trump administration's broader assault on climate science see some merit in a more targeted approach under Section 111.
'We've been telling folks for a while that we thought it was easier for them to make a run at the power sector or the oil and gas sector than the vehicle sector, just because of the word 'significantly' in the statute,' said Jeff Holmstead, who served as EPA air chief under former President George W. Bush.
But if EPA's bid to label power plants as insignificant contributors to harmful pollution survives the inevitable legal challenges, it could absolve the agency from regulating a wide range of stationary emissions sources under Section 111.
That's because the U.S. power sector is a major source of climate pollution. Declaring that it doesn't contribute 'significantly' to pollution could rule out regulation of any source category that emits less pollution — which would be nearly all of them.
'If the courts agree that greenhouse gas emissions from the power sector do not 'significantly contribute' to air pollution that endangers public health or welfare, then this would prevent EPA from regulating greenhouse emissions from any industrial sector,' said Holmstead.
Transportation would be a notable exception. It emits more and is regulated under a different section of the law, so the move wouldn't affect tailpipe emissions rules.
If the courts agree with EPA's proposed threshold for what constitutes a 'significant' contribution, that could also create hurdles for future administrations, experts said.
'They may well get a judicial decision on what it means to contribute significantly under Section 111 of the Clean Air Act,' said Jonathan Adler, a conservative legal scholar and founding director of Case Western Reserve University's environmental law center. 'That would potentially lock that in place. Not just for power plants, but arguably for other stationary source categories.'
Coal- and gas-fired power plants released 31 percent of domestic CO2 emissions from fossil fuels combustion in 2023, according to EPA's own emissions inventory, which the Environmental Defense Fund released this month after obtaining it via a Freedom of Information Act request. That's more than any other source category except transportation.
EPA's inventory showed that industrial energy use collectively accounted for 26.3 percent of CO2 from fossil fuels combustion in 2023 — a significant share of emissions but less than the power sector.
The 3% problem
Section 111 of the Clean Air Act doesn't set a threshold above which sectors are deemed to contribute 'significantly' to climate pollution.
The New York Times' reporting hints that EPA may be preparing to propose '3 percent of global emissions' as that threshold, but experts agree that the agency would need to give a strong justification for choosing that as the cutoff.
Only six economies emit more than 3 percent of global emissions, comprising China, the United States, India, the European Union, Russia and Brazil. In other words, the U.S. power sector is responsible for more greenhouse gas emissions than the national emissions of most countries.
EPA also has the challenge of seeking to introduce this threshold — for the first time in the Clean Air Act's 50-year history — a year after the Supreme Court issued a landmark decision to sharply limit the degree of deference courts afford to agencies in interpreting vaguely worded statutes. The Loper Bright v. Raimondo decision upended a decades-old legal precedent known as the Chevron doctrine that directed courts to give agencies the benefit of the doubt in their 'reasonable' interpretations of laws when Congress' intent was unclear.
'This is a matter of statutory interpretation,' said Joe Goffman, who served as EPA air chief in the Biden administration. 'I think at least in passing, they will regret the demise of Chevron deference.'
Holmstead noted that EPA would benefit from statutory language that instructs the EPA administrator to decide 'in his judgment' whether a source category contributes significantly to harmful pollution.
Robert Sussman, who served as senior policy counsel at EPA during the Obama administration, said that EPA would also need to explain a rule from Trump's first term — which was never implemented — that sought to make 3 percent of domestic greenhouse gas emissions the threshold for a finding of significant contribution under Section 111.
That's a much lower bar than 3 percent of global emissions, and EPA said explicitly at the time that the power sector qualified as contributing significantly.
'They would need to demonstrate why the rule that they themselves promulgated in the first term no longer represents their thinking,' Sussman said.
The Trump EPA's strategy on endangerment shows it trying to avoid a frontal assault on climate science, relying instead on 'a fairly narrow legal formulation that they can apply without much effort,' said Sussman.
The administration hasn't devoted any time to building an alternative scientific record to support its bid to overturn the foundational scientific finding — as it considered doing during Trump's first term. Less than a month after inauguration day, EPA sent the White House recommendations for upending the agency's 2009 endangerment finding, which declared that greenhouse gas emissions endangered public health and welfare. The power plant repeal proposal followed a couple of months later.
But Sussman said the agency would need to provide analysis based on science for the criteria it proposes for sources that 'contribute significantly.'
'They will actually have to, I think, get into the science of climate change here in order to have an intelligent position on what is a 'significant contribution,'' he said. 'If you just pick a number out of the air — like 3 percent — how can that number be meaningful without regard to the context of the pollution problem that you're trying to address?'
Environmental lawyers see another statutory problem. EPA has always considered all the pollution from a source category — like power plants or oil refineries — when interpreting Section 111. That means the agency might have to argue that U.S. power plants don't contribute significantly to any harmful pollution, not just planet-warming emissions, to undo its 1971 decision to list fossil fuel power plants under Section 111.
'Administratively, this is a through line of EPA's interpretation,' said Patrick A. Parenteau, a senior fellow of climate policy in the Environmental Law Center at Vermont Law School.
The Biden EPA did discuss the greenhouse gas emissions from U.S. power plants as part of the carbon rule it finalized last year. It stated the sector was responsible for 4 percent of global heat-trapping emissions, based on 2021 data. But Goffman said that information was included at EPA's discretion, not because Section 111 required a separate significant contribution finding for power plant carbon emissions.
But Holmstead said courts have never weighed in on whether that EPA interpretation is the best reading of the statute. And he said he thought the Trump administration was right to argue — as it likely will — that the statute requires a dedicated finding for each pollutant, not just for source categories.
'It doesn't make any sense to say that EPA can regulate any pollutant that it wants, even if there's no sense in regulating it,' he said. 'I don't always agree with the legal positions of this administration, but I think they're right on this one.'