The issue over the mercury rule has focused on costs and benefits. Mr. Wheeler’s E.P.A. argues that the Obama administration was wrong to include “co-benefits” that would result from the rule. The scrubbers that remove mercury from coal plant emissions also reduce other pollutants, especially particulates, which are deadly, so this co-benefit keeps lethal pollution out of the air.

Reductions in heart and lung disease from particulates prevent up to an estimated 11,000 premature deaths a year. And those other hazardous air toxics coming from industrial coal stacks? As someone who has survived kidney cancer — my oncologist vaguely explained it was “one of those environmental cancers” — I can promise you these aren’t things we want to breathe: probable carcinogens like cadmium, arsenic, benzene and formaldehyde, among others. The cost associated with harm from these was not even monetized by the E.P.A. Keeping them out of our air is a “freebie.”

If anything, the benefits of reducing mercury have been vastly understated. Since the rule was finalized, the science documenting the severe health impacts of mercury has become even stronger. New studies show that the quantified benefits of reducing mercury are now in the billions of dollars; a study published in the journal Environmental Health in 2017 estimated that the societal costs associated with the neurocognitive deficits from methylmercury exposure in the United States that year was $4.8 billion .

Among those urging the E.P.A. to leave the mercury standards alone was, surprisingly, the nation’s electric utility industry, which found that implementation cost far less than they had anticipated. Power industry experts indicate the true costs of the standards are $2 billion — or less than a quarter of what the agency originally estimated. Mr. Wheeler ignored the industry’s request that the standards be left in place. As the Rev. Mitch Hescox, president of the Evangelical Environmental Network, wrote in The Christian Post, addressing Mr. Wheeler’s legalistic cover of not overturning the rule but making it vulnerable to legal attack: “God is not fooled — and neither are we.” He added, “ We’ll never give up on protecting children and the unborn from mercury pollution. Never.”

President Trump’s pro-polluter agenda is profoundly radical — and immoral. We are in danger of normalizing the president’s ruthless disregard for health- and science-based protections. Mr. Wheeler’s cynical ploy to upend the mercury regulations is emblematic of his agenda. His fingerprints are all over proposed rollbacks of environmental regulations covering cars, carbon emissions from power plants, coal ash and more. For this destructiveness, Mr. Trump praised him in November, saying he had “done a fantastic job and I want to congratulate him.”

Mr. Wheeler’s E.P.A. is also weakening implementation of a bipartisan law passed in 2016 protecting the public from toxic chemicals; people with chemical industry résumés dominate his staff. And Mr. Wheeler has sought to roll back an Obama-era rule requiring energy companies to monitor and repair leaks of methane; these leaks can occur from the moment a well is fracked until the gas gets to your home. Methane is an extremely powerful and swift contributor to global warming. Rather than move the country onto a path toward climate safety, Mr. Trump and Mr. Wheeler are leading us — and the world — closer to mutually assured destruction.

Mr. Wheeler is more media savvy than Mr. Pruitt ever was, and that makes him more dangerous. His nomination to run the E.P.A. is among the most consequential and cynical of all the cabinet appointments that Mr. Trump has proposed. Mr. Wheeler’s disregard for the agency’s core mission — to protect public health and the environment — is brazen. But what else should we expect from a former coal industry lobbyist?

Andrew Wheeler has demonstrated over and over again why he should not be entrusted with protecting us from harm. If his failure to do one single thing to address the global warming catastrophe isn’t bad enough to stop this nomination, perhaps his decision to upend the mercury rule, which could threaten the brains of tiny babies, will wake up senators. No one voted to make America dirty again .

Dominique Browning is the senior director and a co-founder of Moms Clean Air Force.

Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram.