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EPA Reaffirms Underpinnings of Mercury and Air Toxics Standards for Power Plants

The Environmental Protection Agency on Feb. 17 issued a final rule that reaffirmed the scientific, economic, and legal underpinnings of the 2012 Mercury and Air Toxics Standards for power plants, which required significant reductions of mercury, acid gases, and other harmful pollutants.

The final rule, which responds to President Biden’s January 20, 2021, Executive Order 13990, “Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis,” reverses a rule issued by the previous administration in May 2020.

The final rule leaves the current emissions standards unchanged. “When weighing the substantial burden that hazardous air pollutants, including mercury, impose on public health against the reasonable costs of controlling these emissions, EPA finds that it is appropriate and necessary to regulate emissions of air toxics from power plants under the Clean Air Act,” EPA said in a news release.

The agency said it is also continuing to consider the MATS Residual Risk and Technology Review, as directed by Executive Order 13990, to determine whether more stringent protections for hazardous air emissions from power plants are feasible and warranted and expects to address that review in a separate action.

The initial appropriate and necessary finding was made in 2000 and affirmed in 2012 and 2016. In May 2020, the Trump Administration reversed EPA’s 2016 finding, the costs of regulating hazardous air pollutants (HAPs) from coal and oil fired electric generating units grossly outweigh the quantified HAP benefits. However, is 2021, Executive Order 13990 directed EPA to review that finding and consider an action to rescind it.

In its Feb. 17 action, EPA determined that the 2020 action was “based on a fundamentally flawed interpretation of the Clean Air Act that improperly ignored or undervalued vital health benefits from reducing hazardous air pollution from power plants,” it said.

EPA reaffirmed that “it is appropriate and necessary to regulate emissions of hazardous air pollutants from coal- and oil-fired power plants.” In 2022 APPA submitted comments supporting the restoration of the appropriate and necessary finding to help secure critical regulatory and business certainty for power sector which had spent $18 billion to comply with the MATS rule since it became effective.

 In 2021, APPA, National Rural Electric Cooperative Association, and the Edison Electric Institute commissioned a study to evaluate particulate matter, hydrogen chloride, and mercury emissions measurements from a representative subset of coal-fired electric generating units.

The evaluation was conducted to understand the impact of potentially lower particulate matter, hydrogen chloride, and mercury emission rates, if EPA were to propose to revise the Mercury and Air Toxic Standards residual risk and technology review rule for coal and oil-fired plants.