The U.S. Environmental Protection Agency is moving to bolster its authority to enforce mercury emissions rules for coal- and oil-fired powerplants.

EPA wants to reverse a Trump administration rule that undercut the legal basis to regulate mercury and other pollutants from those plants, and reaffirm public health and environmental benefits of reducing air pollutants through the 2012 Mercury and Air Toxic Standards (MATS), the agency said Jan. 31. 

Exposure to mercury can result in neuro-developmental delays and other health risks. Powerplants are the biggest source of mercury, EPA says. Officials estimate MATS and power sector advancements contributed to an 86% reduction in mercury emissions from power plants from 2010 to 2017.

The Trump administration never rescinded MATS but narrowed EPA's ability to incorporate health and environmental benefits into its cost-benefit analyses.

In its Jan. 31 proposal, EPA said the 2020 action "was based on a fundamentally flawed interpretation of the Clean Air Act" that undervalued the health benefits of reducing hazardous air pollutants from powerplants. The new proposal reaffirms legal arguments for the 2012 emissions standards and enables EPA to evaluate whether more stringent controls are needed. 

The proposal has support from environmental activists and some power sector industry groups. Tom Kuhn, president of the Edison Electric Institute, said in a statement that its member companies have been implementing MATS for years.

“Restoring the appropriate and necessary finding enables electric companies to 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,” Kuhn said.

The move follows an executive order issued by President Joe Biden last year directing federal agency heads to review Trump-era policies for anything that would be a hurdle in his administration's goal to combat climate change, specifically highlighting emissions from coal-fired power plants. In its announcement, EPA says the 2020 Trump administration action overlooked health benefits of reducing air pollution.

“Sound science makes it clear 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 agency says it will hold a virtual public hearing on its proposal and that it will accept public comment for 60 days.