The EPA’s science advisers are offering to help the agency figure out how to identify and estimate the side benefits of targeting power plant and automobile releases of air pollution, especially hazardous ones like mercury.

Their insight will help the Environmental Protection Agency determine how to calculate the costs and benefits of reducing toxic air pollutants from power plants and other industrial sources without relying too heavily on side benefits, or co-benefits as the agency calls them.

This assistance is particularly timely, as the House Energy and Commerce Committee’s oversight panel is poised at a May 21 hearing to probe the EPA’s use of co-benefits. The hearing will examine EPA’s December 2018 proposal (RIN: 2060-AT99), published in February, related to mercury emissions from power plants.

The EPA is seeking to eliminate what it sees as the agency’s past over-reliance, in calculating the costs and benefits of the mercury emissions regulation, on the regulation’s side benefits that flow from reducing airborne particle pollution. Airborne particle pollution is linked to heart and lung diseases, while mercury is considered a neurotoxin.

Broader Issue Seen Meriting Attention

The Science Advisory Board said this broader question of co-benefits in air quality rules needs close attention because in some EPA rulemakings, such as the 2012 mercury emissions limits, the vast majority of the quantified benefits of clean-air regulations are co-benefits, according to the project’s details.

The board will take up this project with EPA officials when they meet June 5 and 6 in Washington.

The advisers say the exercise ensuring that the EPA accurately estimates co-benefits isn’t “trivial” because the practice of counting these side benefits of federal clean-air regulations has sparked controversy before.

“Questions have been raised as to whether EPA is overestimating or underestimating co-benefits in various rulemakings,” the advisers wrote.

They said a regulation aimed at reducing hazardous air emissions from stationary or mobile sources may also reduce emissions of fine particles and precursors to smog. But the side benefit could occur because the pollution-control technology used to reduce the target pollutant may also reduce other pollutants.

‘Clear Justification’

Environmental groups, such as the legal nonprofit Earthjustice, are unable to find “a clear justification” for the EPA science advisers’ efforts.

“The proposal notes the significant role that co-benefits have played in prior EPA decisionmaking, and then asserts that this justifies scientific review of how co-benefits are determined. However, my quick read doesn’t find an explanation as to why the determination of co-benefits is in special need of review, as opposed to ‘direct’ benefits,” David Baron, Earthjustice managing attorney in Washington, told Bloomberg Environment in a May 20 email.

The EPA didn’t immediately respond to Bloomberg Environment when asked whether it is backing the board’s effort as it sifts through the comments on its mercury regulation.

The agency also isn’t defending its proposal before the House energy panel, where it plans to rely on an industry lawyer to explain its approach.

Adam Gustafson, a partner with Boyden Gray & Associates plans to argue that the agency is responding to a U.S. Supreme Court ruling and merely fixing “an accounting error” that the Obama EPA made in overestimating the co-benefits of reducing mercury pollution, at the expense of the actual benefits. He said in his prepared remarks he hopes that the EPA will follow this approach in all future regulations.

In contrast, Janet McCabe, the EPA’s former acting assistant administrator for air and radiation , will speak against the proposal. Her argument is that EPA’s effort in essence will set a precedent in how it estimates costs and benefits in future regulations.

McCabe, who is now an Indiana University Robert H. McKinney School of Law professor, is correct in reading that the EPA’s action on mercury could be a major shift because the EPA is in the process of crafting a proposal to change the way it calculates costs and benefits in all environmental regulations.

Party Lines Drawn

Rep. Diana DeGette (D-Colo.), who chairs the energy subcommittee, said May 20 that she is particularly concerned with the agency’s efforts to undermine the mercury rule, and its attempts to establish a new precedent that would prevent regulators from considering the full range of public health benefits of proposed regulations.

Rep. Greg Walden (R-Ore.), the committee’s ranking member, is gearing up to remind his Democratic colleagues that the Clean Air Act is silent on on whether, or how, the EPA should consider co-benefits in the rulemaking process.

“I remind my colleagues that this body has the ability to change the law and statutorily determine whether and how co-benefits should be considered. I’ve seen no bills introduced to date on this point,” according to Walden’s prepared testimony for the hearing.