Biden E.P.A. Reinstates Mercury Limits Weakened Under Trump

WASHINGTON — The Biden administration on Friday restored the legal foundation of an Obama-era regulation governing mercury, a pollutant from power plants that can damage brain development in babies and cause heart disease in adults.

The regulation had been stripped away by the Trump administration. Its revival paves the way for the federal government to set even stricter controls on mercury emissions, something the Environmental Protection Agency under President Biden is expected to do.

“For years, mercury and air toxics standards have protected the health of American communities nationwide, especially children, low-income communities, and communities of color who often and unjustly live near power plants,” E.P.A. Administrator Michael S. Regan said. “This finding ensures the continuation of these critical, lifesaving protections while advancing President Biden’s commitment to making science-based decisions and protecting the health and well being of all people and all communities.”

Mr. Regan did not say if or when E.P.A. will publish a stronger mercury regulation, although the agency has already begun the legal process required for reviewing and updating the current standard.

The regulatory action announced Friday is one in a series of moves by the Biden administration to first restore and then strengthen the many environmental rules that were erased or weakened under President Donald J. Trump.

While Democrats in Congress last year passed the nation’s first major climate law, the midterm takeover of the House of Representatives by Republicans effectively ensures that no new climate or pollution control legislation will be enacted in the remainder of President Biden’s first term. He is instead expected to lean on his executive authority to execute the rest of his climate agenda.

In 2021, the E.P.A. restored and slightly strengthened an Obama-era limit on auto pollution that had been gutted by the agency under Mr. Trump. It is expected as soon as next month to unveil a set of much tougher rules on car and truck pollution that would be designed to accelerate the nation’s transition to all-electric vehicles.

The E.P.A. has limited mercury emissions from coal plants since 2012. But during the Trump administration, the agency concluded that the rule’s cost to industry outweighed its benefits and therefore it was no longer “appropriate and necessary.”

That finding allowed the Trump administration to stop enforcing the mercury limit, even though it remained on the books. Many environmental law experts saw the Trump administration’s actions as a first step toward eliminating other pollution limits.

The Biden administration will now return to an Obama-era method of calculating the impact of regulation in a way that considers collateral benefits, such as reducing fine particulate matter and smog, when estimating the gains expected from lower mercury emissions.

Using that method would enable the E.P. A. to conclude that the public health benefits of limiting mercury, such as prevention of disease and premature deaths, outweigh the costs to industry. That would provide the legal justification to enforce the existing mercury regulations.

“Trump took away the foundation of the house but the house was still there,” said Matthew Davis, a former E.P.A. official who helped to write the mercury rule and now works for the League of Conservation Voters. “So this puts back the foundation.”

The restoration of the rule also brought rare praise from the very industry it regulates. Many power plant operators had installed expensive “scrubber” technology to comply with the rule during the Obama administration.

Tom Kuhn, president of the Edison Electric Institute, which represents investor-owned electric utilities, said that the companies had already been complying with the rule.

“EEI’s member companies, and the electric power industry collectively, have invested more than $18 billion to install pollution control technologies to meet these standards,” said Mr. Kuhn in a statement. “With the appropriate and necessary finding restored, electric companies can remain focused on getting the energy we provide as clean as we can as fast as we can, while maintaining the reliability and affordability that our customers value.”