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On February 16, 2012, EPA promulgated National Emission Standards for Hazardous Air Pollutants for Coal- and Oil-fired Electric Utility Steam Generating Units (77 FR 9304). The rule (40 CFR part 63, subpart UUUUU), commonly referred to as the Mercury and Air Toxics Standards (MATS), includes standards to control hazardous air pollutant (HAP) emissions from new and existing coal- and oil-fired electric utility steam generating units (EGUs) located at both major and area sources of HAP emissions. There have been several regulatory actions regarding MATS since February 2012, including a May 22, 2020, action that completed a reconsideration of the appropriate and necessary finding for MATS and finalized the residual risk and technology review (RTR) conducted for the Coal- and Oil-Fired EGU source category regulated under MATS (85 FR 31286). The Biden Administration's Executive Order 13990, Protecting Public Health and the Environment and Restoring Science To Tackle the Climate Crisis, "directs all executive departments and agencies (agencies) to immediately review and, as appropriate and consistent with applicable law, take action to address the promulgation of Federal regulations and other actions during the last 4 years that conflict with these important national objectives, and to immediately commence work to confront the climate crisis." Section 2(a)(iv) of the Executive Order specifically directs that the Administrator consider publishing, as appropriate and consistent with applicable law, a proposed rule suspending, revising, or rescinding the ‘‘National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units—Reconsideration of Supplemental Finding and Residual Risk and Technology Review,’’ 85 FR 31286 (May 22, 2020). As directed by Executive Order 13990, EPA reviewed the RTR portion of the May 22, 2020 final action and, proposed to update and strengthen the MATS on April 24, 2023 (88 FR 24854). EPA finalized the Revocation of the 2020 Reconsideration and Affirmation of the Appropriate and Necessary Supplemental Finding on February 15, 2023 (88 FR 13956).

Statement of Need:

Executive Order 13990, “Protecting Public Health and the Environment and Restoring Science To Tackle the Climate Crisis,” directs EPA to review the May 2020 RTR. EPA will issue the results of the review in a notice of proposed rulemaking and will solicit comment on the review.

Summary of the Legal Basis:

CAA section 112, 42 U.S.C. 7412, provides the legal framework and basis for regulatory actions addressing emissions of hazardous air pollutants from stationary sources.

Alternatives:

EPA has evaluated several options for reviewing the RTR and will take comment on the review.

Anticipated Costs and Benefits:

EPA projects the present value of net benefits to be $2.4 billion to $3.0 billion. This includes $1.2 billion to $1.9 billion in health benefits, $1.4 billion in climate benefits, and compliance costs of $230 million to $330 million. EPA projects the estimated annualized value net benefits to be $300 million to $350 million. This includes $170 million to $220 million in health benefits, $170 million in climate benefits, and compliance costs of $33 million to $38 million. EPA projects that the proposed changes would result in the following emission reductions in the year 2035: 

•                 82 pounds of mercury 
•                 800 tons of fine particulate matter (PM2.5) 
•                 8,800 tons of sulfur dioxide 
•                 8,700 tons of nitrogen oxides 
•                 5 million tons of carbon dioxide

Risks:

The results of the 2020 RTR showed that emissions of HAP from coal- and oil-fired power plants have been reduced such that residual risk is at in acceptable level. EPA reviewed the 2020 residual risk assessment and determined the risk review was conducted using approaches and methodologies that are consistent with prior risk analyses and reviews for other industrial sectors. Although EPA is not reopening the 2020 risk review, the proposed standards under the technology review would achieve reductions in HAP emissions from power plants and likely to reduce HAP exposures to affected populations.