“For a lot of folks, this was just another example of Obama regulatory overreach,” said Jeffrey R. Holmstead, a partner at the law firm Bracewell who served as E.P.A. air chief under the second President George Bush.
The Obama administration itself had broadly accepted that it is difficult to put a specific dollar-figure on some health benefits, for instance, avoiding lost I.Q. points in infants or other fetal harm that has been linked to pregnant women eating mercury-contaminated fish. For that reason, the original rule argued against using a strict cost-benefit analysis to decide whether the regulation should be imposed, said Joseph Goffman, the executive director of Harvard Law School’s Environmental and Energy Law Program.
The new proposal fundamentally changes that approach. It recognizes that difficult-to-quantify benefits exist, but said the administrator “has concluded that the identification of these benefits is not sufficient, in light of the gross imbalance of monetized costs.”
Ann Weeks, senior counsel for the Clean Air Task Force, an environmental group, criticized the rule as “bean counting,” and said, “This is not tax law. This is public health benefits. It’s a very different calculus.”
Environmental activists said they intend to challenge the new finding in court. If it survives those challenges, observers say it would set a precedent that could make it tougher for the government to justify any number of future regulations.
“There is a likelihood that this rule-making will be the administration’s flagship effort to permanently change the way the federal government considers health benefits,” said Janet McCabe, who ran the E.P.A.’s air office under Mr. Obama.
Mr. Wheeler, in a recent interview, dismissed the idea that utilities, having spent billions of dollars on pollution controls, would stop using them. “It’s not like people are going to start taking off their equipment and start putting mercury into the atmosphere,” he said.