On February 17, 2023, the EPA reaffirmed the scientific, economic, and legal underpinnings of the 2012 Mercury and Air Toxics Standards (MATS) for power plants, which required significant reductions of mercury, acid gases, and other harmful pollutants.
This reinstates an Obama-era legal finding that affirmed the science behind clean air standards, and it reverses a rule issued by the Trump administration in May 2020 that undermined the legal basis for the MATS.
Additionally, it found that the 2020 action “was based on a fundamentally flawed interpretation of the Clean Air Act (CAA) that improperly ignored or undervalued vital health benefits from reducing hazardous air pollution from power plants,” an Agency news release says. “Based on a thorough review of these benefits, the reasonable costs of controls and other relevant factors, the EPA reaffirms that it is appropriate and necessary to regulate emissions of hazardous air pollutants from coal- and oil-fired power plants.”
Controlling these types of emissions has been shown to reduce fatal heart attacks and cancer risks and avoid neurodevelopmental delays in children.
“For years, [MATS] have protected the health of American communities nationwide, especially children, low-income communities, and communities of color who often and unjustly live near power plants,” said EPA Administrator Michael S. Regan in the news release. “This finding ensures the continuation of these critical, life-saving protections while advancing President Biden’s commitment to making science-based decisions and protecting the health and wellbeing of all people and all communities.”
The final rule leaves the current emissions standards unchanged and ensures the continuation of public health protections provided by these requirements. When weighing the substantial burden that hazardous air pollutants, including mercury, impose on public health against the reasonable costs of controlling these emissions, the EPA stated it “finds that it is appropriate and necessary to regulate emissions of air toxics from power plants under the Clean Air Act (CAA). The Agency is also continuing to consider the MATS Risk and Technology Review, as directed by Executive Order 13990, to determine whether more stringent protections for hazardous air pollution from power plants are feasible and warranted and expects to address that review in a separate action.”
The EPA has found that the MATS, combined with technological advances made by power plants, has been effective in reducing harmful emissions. The EPA has estimated that by 2017, mercury emissions from power plants were reduced by 86 percent, acid gas emissions were reduced by 96 percent, and nonmercury metal emissions were reduced by 81 percent compared with pre-MATS levels in 2010. After a reassessment of costs now that the MATS has been implemented, the EPA concludes that the cost for the power sector to comply with the MATS was likely billions of dollars lower than originally estimated.
“While some in the coal industry oppose the return to enforcing the mercury rule, many electric utilities that operate coal-burning power plants are expected to support it, as they had already invested years ago in the ‘scrubbers’ to tamp down emissions,” reports The New York Times. “A lawyer for the Edison Electric Institute [EEI], which represents investor-owned electric utilities, wrote in an email that the companies were already complying with the … MATS rule.
“EEI’s member companies have fully implemented the MATS rule and will continue to operate those pollution control technologies,” wrote Alex Bond, deputy general counsel for the institute, according to The New York Times. “The repeal of the underlying legal basis for MATS introduced new uncertainty and risk for companies that still are recovering the costs for installing those control technologies, and we appreciate the U.S. [EPA’s] efforts to review and reinstate the appropriate and necessary determination.”
Before the MATS, coal- and oil-fired power plants were by far the largest domestic source of mercury and other toxic pollutants such as hydrogen chloride and selenium, according to the EPA. “They were also among the largest domestic emitters of arsenic, chromium, cobalt, nickel, hydrogen cyanide, beryllium, and cadmium,” adds the Agency news release.