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Power Plant Mercury Limits Still Need Tightening, Say Advocates

Feb. 1, 2022, 10:19 PM

Reaffirming the legal basis for mercury power plant rules is a welcome move away from a controversial Trump-era rollback and should pave the way for even stronger federal regulation, clean air advocates say.

“There’s been new science showing mercury is even worse than we thought, and especially for environmental justice communities,” according to Temple University Beasley School of Law professor Amy Sinden.

And concern for those communities is likely “a significant driver” when considering justifications for rules like mercury standards under the Biden administration, according to David Loring, an environmental partner at Schiff Hardin LLP.

The Biden administration on Monday reinstated an “appropriate and necessary” finding that provides the legal underpinnings for Mercury and Air Toxics Standards, language that was scrapped by the previous administration in 2020.

The move bolsters the rule’s legality and asks for further review of technologies, but stops short of strengthening any requirements. It does leave the door open for future rulemaking through analysis of other public health benefits aside from cost to industry.

“A lot of the justification for these qualitative benefits are focused on the impact of these rules on [environmental justice] areas,” he said. “These are analyses and discussions we are going to see in future EPA rulemakings, whether it’s MATS or anything else that comes down their pipeline.”

Justification Basis

The Trump administration scrapped the “appropriate and necessary” finding to take emphasis off “co-benefits” such as positive health effects in regulation decision-making. The reasoning was meant to rely solely on what can be quantified in a cost-benefit analysis, like increased price tags for companies.

The EPA’s restoration of that finding affirms the agency’s ability to consider more qualitative factors, which eventually could be used to undergird a more stringent rule, Loring noted.

“Limiting pollutants targeted by MATS inevitably curbs other pollutants like particulate matter as well, leading to enormous public health co-benefits,” NYU Institute for Policy Integrity director Richard Revesz said in a statement.

“By considering both direct and indirect benefits in this decision, EPA revives analytic best practices cast aside by the Trump administration,” Revesz said.

Not a Bullet for Carbon

However, the proposed rule shouldn’t be construed as a precursor to alternative carbon reduction measures for power plants, according to Natural Resources Defense Council climate and clean energy program director David Doniger.

The Clean Air Act works through different programs that intersect some of the same industries— particularly through the outsize emissions contributions of the power sector—which leads to cross-reductions in emissions regulated by other programs.

But looking at mercury regulations too closely through the lens of eventually getting to carbon is “just wrong,” Doniger said.

“You regulate mercury because mercury is dangerous, you regulate sulfur dioxide because sulfur dioxide is dangerous,” he said. “Each of these things has an endangerment determination associated with it and it is EPA’s obligation to use the different parts of the Clean Air Act that pertain to those kinds of things.”

The EPA’s proposal can’t be considered the beginning of a “crackdown,” Doniger said. But it does mend the crack made by the Trump administration in landmark standards that reduced deadly air and water pollution by up to 86%.

Regulatory Certainty

Reinstating the Obama-era language also provides regulatory certainty around a rule that industry has already spent millions on to comply with for years.

“The power industry currently has been asking for this reaffirmation of the appropriate necessary finding because they want stability,” Doniger said.

The original rule was “transformational” for electric power sector compliance, according to Heath Knakmuhs, vice president and policy counsel for the U.S. Chamber of Commerce’s Global Energy Institute.

“The ‘appropriate and necessary’ foundation for these standards protects these investments and provides needed regulatory certainty supporting the continued operations and maintenance of these important emissions controls,” he said in a statement.

To contact the reporter on this story: Jennifer Hijazi in Washington at

To contact the editor responsible for this story: Rebecca Baker at