The Environmental Protection Agency finalized a repeal of tighter mercury and air toxics limits for coal-fired power plants on February 20, 2026, rolling back Biden-era amendments and reverting emission standards to 2012 levels. EPA Administrator Lee Zeldin announced the decision at Mills Creek Power Plant in Kentucky, framing it as relief for baseload power generation. The move strips away stricter particulate matter thresholds, updated lignite mercury limits, and continuous emissions monitoring requirements that the previous administration had locked in less than two years ago.
What the Repeal Removes and What It Costs
The finalized action targets three specific provisions added to the Mercury and Air Toxics Standards in May 2024: a tighter filterable particulate matter standard that had dropped from 0.030 to 0.010 lb/MMBtu, a revised mercury limit for lignite-burning plants, and a mandate requiring continuous emissions monitoring systems for particulate matter. By undoing all three, the EPA effectively restores the regulatory framework that has governed coal and oil-fired utilities since 2012. In its own repeal notice, the agency estimates $670 million in savings for the power sector, though it does not specify whether that figure is annual or cumulative, or how it breaks down between avoided capital investments and operating costs.
At the proposal stage, the EPA had projected even larger relief, claiming $1.2 billion in savings over a decade from a broader package of power-plant deregulation. The gap between the two numbers likely reflects the narrower scope of the final MATS-specific action compared with the wider proposal, which bundled several rule changes together. For plant operators, the practical effect is immediate: they no longer need to plan capital spending on upgraded monitoring equipment or retrofit pollution controls to meet the tighter 0.010 lb/MMBtu particulate threshold that Peabody Energy and other coal producers had flagged in regulatory filings as a material compliance risk. Utilities that had already begun engineering work to meet the 2024 standards must now decide whether to halt projects or continue them voluntarily in anticipation of future policy swings.
How the 2024 Standards Came About
The 2024 amendments that are now being unraveled were the culmination of a lengthy review of the original 2012 Mercury and Air Toxics Standards, which set national limits on hazardous air pollutants from coal- and oil-fired power plants. Under the Biden administration, the EPA revisited those limits and concluded that tighter controls on filterable particulate matter and mercury from lignite units were justified by updated health and technology assessments. The final rule, published as a national emissions standard for hazardous air pollutants, also required more robust monitoring to ensure that plants were consistently meeting their obligations rather than relying on periodic stack tests.
Even before the 2024 rule was finalized, the current administration signaled it would take a different approach. In 2025, the EPA announced it would reconsider the tightened limits, focusing especially on coal-fired power plants that argued the new requirements were too stringent for older units. That reconsideration process laid the groundwork for the 2026 repeal by reopening the administrative record and inviting industry groups and coal-state officials to submit data on costs, reliability concerns, and claimed technological barriers. The agency’s pivot underscores how quickly Clean Air Act standards can be reinterpreted as administrations change, even when underlying statutory language remains the same.
Presidential Proclamation Extends Compliance Deadlines
Alongside the final rule, a separate presidential proclamation invokes Clean Air Act section 112(i)(4) to grant compliance exemptions for power plants that were already facing the 2024 amendments. According to the document sent to Congress, the compliance date for affected stationary sources shifts from July 8, 2027, to July 8, 2029. That two-year extension functions as a backstop: even if courts later restore the Biden-era standards, covered plants would not face enforcement until the end of the decade. The EPA had earlier signaled it was considering this exemption authority when it launched its formal reconsideration of the 2024 MATS update, and the proclamation now locks in that additional breathing room for operators.
Using section 112(i)(4) in this way is unusual. The provision was designed to let individual sources seek case-by-case deadline relief, not to grant blanket exemptions across an entire regulated class. By stretching the statute’s language through a presidential proclamation rather than a standard rulemaking, the administration sidesteps the public comment process that typically accompanies changes to Clean Air Act compliance timelines. That procedural shortcut is almost certain to draw legal scrutiny, especially given the ongoing D.C. Circuit litigation over the underlying 2024 rule. It also raises separation-of-powers questions about how far executive branch discretion can go in reshaping congressionally mandated pollution control schedules without fresh legislation.
23-State Legal Challenge and the Courts
The rollback lands in the middle of active litigation. North Dakota and 22 other states had already asked the D.C. Circuit to stay the 2024 MATS amendments in the case captioned North Dakota v. EPA, No. 24-1119, arguing the tighter standards were technically infeasible and economically unjustified. The North Dakota attorney general framed the coalition’s argument around both reliability and cost, asserting that stricter limits would force premature retirement of coal plants that still provide significant baseload capacity. That case has not yet reached a final resolution, and the EPA’s decision to repeal the contested provisions could complicate the court’s review by mooting the states’ challenge while simultaneously creating new grounds for environmental groups to sue over the rollback itself.
MATS has a long history of judicial conflict. A Congressional Research Service brief traces repeated court battles over the Clean Air Act’s requirement that mercury regulation be “appropriate and necessary,” a phrase that has generated conflicting interpretations across administrations. The Supreme Court weighed in on the original 2012 rule, and lower courts have revisited the standards multiple times since, often sending the EPA back to redo its cost-benefit analysis or reconsider how it accounts for co-benefits from particulate reductions. Each change of administration has triggered a new round of reconsideration, creating a regulatory cycle that gives neither industry nor environmental advocates lasting certainty and leaves communities exposed to shifting levels of hazardous air pollutants.
Health Warnings and the Deregulatory Pattern
Environmental organizations responded sharply to the announcement. Reporting from Reuters noted that advocacy groups warned the rollback puts babies and vulnerable communities at heightened risk from mercury exposure, a neurotoxin that accumulates in fish and enters the food chain. Public health experts have long emphasized that mercury and other hazardous air pollutants disproportionately affect low-income neighborhoods and communities of color located near coal plants, where residents already face elevated rates of asthma and cardiovascular disease. By easing particulate and mercury controls, critics argue, the EPA is accepting higher levels of emissions that will translate into more hospital visits, lost workdays, and long-term developmental harms for children.
Environmental advocates also see the MATS repeal as part of a broader deregulatory pattern. Coverage by the Guardian places the decision alongside other efforts to ease constraints on fossil fuel infrastructure, arguing that the administration is prioritizing short-term relief for coal producers over long-term health protections. Industry groups counter that the original 2012 standards already drove substantial reductions in mercury and toxics, and that further tightening would have delivered diminishing returns at high cost. As legal challenges move forward and future administrations weigh their own options, the fate of MATS will continue to serve as a test case for how aggressively federal agencies can regulate hazardous pollutants while balancing economic and political pressures.
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*This article was researched with the help of AI, with human editors creating the final content.
