Under the Obama administration, the EPA stated that it had the authority under the Clean Air Act to regulate mercury and other toxic metal emissions from power plants as long as EPA officials determined it was "appropriate and necessary."
The Trump administration withdrew that determination in 2020, claiming that regulators made mistakes in calculating the costs and benefits of the rules. Following that revocation, a coal producer petitioned the United States Court of Appeals for the District of Columbia Circuit to overturn the regulations that Obama-era officials had relied on to regulate air pollutants.
The EPA stated in reinstating the policy that controlling toxic emissions reduces cancer risks and neurodevelopmental delays in children.
"Sound science shows that we need to limit mercury and toxins in the air to protect children and vulnerable communities from dangerous pollution," EPA Administrator Michael Regan said.
The Wall Street Journal reported last week that the EPA was considering toughening rules on power plants as part of President Biden's efforts to reduce greenhouse-gas emissions, which are attributed to climate change.
If approved, Monday's proposal would be a setback for coal miner Westmoreland Mining Holdings LLC, which had asked the court to overturn regulations requiring operators of the country's coal- and oil-burning power plants to reduce emissions, including by installing filtration equipment that strained pollutants from the air. A decision on that request has yet to be made by a judge.
The existing regulations, which set an April 2015 compliance deadline for operators, have been effective at reducing air pollutants emissions, according to public-health and environmental groups. According to an EPA estimate, mercury emissions from power plants fell by 86% in 2017 compared to 2010.
Prior to the regulations, power plants were the largest domestic source of mercury, according to the agency.
Mercury, arsenic, and other toxic metals are released into the atmosphere by power plant smokestacks and make their way into U.S. waterways and the food chain, prompting fish consumption advisories. They have been linked to infant brain development issues as well as cancer.
Federal law requires regulators who make Clean Air Act rules to first determine whether the safeguards are appropriate and necessary. They made that determination in relation to coal-fired and oil-fired power plants in 2000, and it was reaffirmed when the 2012 regulations were released.
Mr. Biden directed EPA officials a year ago to investigate the Trump administration's revocation of mercury emissions rules known as the Mercury and Air Toxics Standards. The EPA will accept comments on Monday's proposal for 60 days.