In April 2023, the EPA announced a proposed rule to strengthen and update the Mercury and Air Toxics Standards (MATS) for coal-fired power plants, achieving important hazardous air pollutant emissions reductions and ensuring standards reflect the latest advancements in pollution control technologies.

If passed, the rule represents the most significant update to date since the MATS was first issued in February 2021.

The EPA reaffirmed the scientific, economic, and legal underpinnings of the standards earlier this year, which reversed “a rule issued by the previous administration that undermined the legal basis for these vital health protections,” according to an EPA news release.

“America is leading the way in innovation, and our work to protect public health is no different. By leveraging proven, emissions-reduction measures available at reasonable costs and encouraging new, advanced control technologies, we can reduce hazardous pollution from coal-fired power plants, protecting our planet and improving public health for all,” said EPA Administrator Michael S. Regan in the Agency news release. “Today’s proposal will support and strengthen EPA’s [MATS], which have delivered a 90 percent reduction in mercury emissions from power plants over pre-standard levels, ensuring historic protections for communities across the nation, especially for our children and our vulnerable populations.”

The MATS requires significant reductions of mercury, acid gases, and other harmful pollutants from coal and oil-fired electric generating units. The proposed rule is projected to reduce emissions of mercury and nonmercury metal pollution, such as nickel, arsenic, and lead, and is also projected to result in emissions reductions of fine particulate matter, sulfur dioxide, nitrogen oxides, and carbon dioxide nationwide.

“Based on its latest assessment of available control technologies and techniques for reducing hazardous air pollutant emissions, EPA is proposing to further reduce – by 67 percent – the emissions limit for filterable particulate matter (fPM) for existing coal-fired power plants,” the news release continues. “This standard is designed to control emissions of nickel, arsenic, and other non-mercury HAP metals from these plants. The proposal also includes cost and feasibility information on achieving even lower levels of fPM emissions, and EPA is taking comment on whether to finalize a more stringent standard.

“In addition, EPA is proposing a 70 percent reduction in the emissions limit for mercury from existing lignite-fired sources, a limit that would ensure these plants achieve the same level of emissions performance as other coal-fired power plants. Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages.”

The proposal also includes improvements and updates to emissions monitoring requirements for coal-fired power plants by requiring continuous emissions monitoring systems to comply with the revised fPM emissions limit.

The proposed rule projects net public health benefits over the 10-year period from 2028 to 2037 to be $2.4 billion to $3 billion, which includes $1.2 billion to $1.9 billion in health benefits, along with projected compliance costs of $230 million to $330 million.

Once the proposed rule is published in the Federal Register, comments will be accepted under Docket # EPA-HQ-OAR-2018- 0794 for 60 days.

For more information, see the EPA MATS website.