Toxic Air Pollutant Mitigation Statute: A Bipartisan Issue or a Universally Accepted Necessity for Human Health

An analysis of the EPA’s 2026 rescission of the Mercury and Air Toxics Standards and what the return to 2012 regulations means for public health and environmental law.

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Published May 2nd, 2026

Written by Allan Schneyderman

On February 24, 2026, the Environmental Protection Agency finalized a rule that rescinded the 2024 Mercury and Air Toxics Standards and reinstated the 2012 standards. This action by the Trump administration, taken under the leadership of EPA head Lee Zeldin, represents an unprecedented and significant shift in how the agency interprets its obligations under the Clean Air Act in relation to Hazardous Air Pollutants from power plants, as per Harvard Law. Under the Biden administration and the 2024 rule, there were three key substantive changes to the more minimalist 2012 standards. The first involved strengthened emission standards for filterable particulate matter in order to better capture non-mercury HAPs such as arsenic, lead, and nickel. The second standard required continuous monitoring systems for coal and oil-fired plants to allow for constant compliance. Finally, the standard involved a more robust requirement that lignite-fired power plants meet the same mercury standards as other coal-fired power plants. The 2026 rule under the Trump administration rescinds all three of these, returning the statutory and regulatory landscape to 2012.

The Clean Air Act establishes National Ambient Air Quality Standards, technology-based standards, and the eight-year review cycle. NAAQS authorizes the EPA to set air quality standards to address widespread pollutants, while the technology-based standards ,MACT, require polluters to use specific technologies to reduce emissions. Section 112 specifically addresses emissions of HAPs, splitting them into major sources (those that emit more than 10 tons per year of a single HAP/25 tons per year of a combination of HAPs) and area sources (those that do not meet the major source threshold). Additionally, according to section 112 of the Clean Air Act stated by the United States Environmental Protection Agency, the EPA must review standards every eight years to ensure they are adequately protecting public health (residual risk review) and to see if technology advances warrant updates. The 2026 rescission is based on a fundamental change in how the EPA conducts Risk and Technology Review . Historically, the residual risk review and technology review have been treated as parallel but nonetheless distinct analyses. The 2026 rescission, however, merges these two reviews, with the assertion that because residual risk to the public is low, cost considerations carry more weight. Residual risk has the specification of cancer risk below 1-in-1 million. With this new logic, the EPA has concluded that updates to technology standards are only necessary and justified if costs to the industry are at the “low end of the range of responsibility.”

The EPA argued that the 2024 standards' cost-effectiveness was significantly higher than previous determinations. The findings revealed that 93% of the industry was in compliance; despite this, the EPA determined that the cost of remediating possible pollutants from the plants was not necessary, given the relatively low health risks. The agency essentially rescinded requirements for continuous monitoring, labeling it as an “unnecessary expense.” In lieu of a more elaborate standard, as made clear in 2024 under the Biden administration, the 2026 EPA reinstated the “Low Emitting EGU”program, which would require less testing of stacks and pollutants if they could demonstrate lowered emissions for three years. Finally, the EPA attested that the 2024 rule failed to account for the “complex composition of lignite," and stricter standards were not achievable for such units.

Earthjustice, a leading environmental law nonprofit, has highlighted numerous legal challenges that could arise from the EPA's recent activity. It characterizes this repeal by the EPA of the 2024 precedent as "unprecedented, unlawful, and unjustified.” There is a human cost of repeal, with data indicating that the repeal of the MCATS will allow coal- and oil-fired power plants to emit higher levels of mercury, arsenic, and other heavy metals. Such emissions are also linked to heart disease and disproportionately impact vulnerable populations. With this comes an overall lack of transparency and monitoring, as made clear by the Environmental Defense Fund. The EDF again emphasizes that the removal of continuous monitoring systems (PM CEMS) would deprive organizations and communities of relevant real-time data while also increasing enforcement gaps. There is an overall challenge to the 2026 holding that the EPA’s decision is explained by economic health incentives. Such moves by the EPA are only propping up a dying coal industry, giving them a free handout, according to the Environmental Protection Network. 

Legal challenges to this rescission of MATS will likely focus on the EPA’s interpretation of the Clean Air Act, its failure to consider regulatory alternatives, and the lack of factual evidence justifying the reversal. A primary legal battleground will involve EPA’s decision to merge residual risk and technology reviews, which the Clean Air Act traditionally treats as parallel processes. Citing Oyez on DHS v. Regents, when an agency rescinds a policy, it must “consider alternatives that are within the ambit of existing policy.” There is both a failure by the EPA to consider such alternatives and overall flaws in regulatory impact analysis.

The health of American citizens should not be determined by mere political affiliation and realignment by one of the most important governing agencies in the United States.

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