Mercury Is Back on the Menu

Can the Trump administration and RFK Jr. credibly speak about protecting families from toxic substances, when their actions consistently push us back into the dark ages of environmental policy? The question is rhetorical (sort of). Today’s article is the latest installment in a drumbeat of reporting on environmental health policy and toxic chemical pollution.

Earlier this year the EPA finalized the repeal of the 2024 Mercury and Air Toxics Standards—federal rules that had limited emissions of mercury, arsenic, lead, and nickel from coal-fired power plants. Reducing our exposure to toxic chemical pollution from polluting industries like coal is one of the best ways to address public health outcomes for communities living nearby, but this latest environmental roll back torpedoes us back to a weaker 2012 baseline. A few months later the American Lung Association released their annual “State of the Air” report which found that nearly half of the kids in the U.S. live in areas with unhealthy air pollution.

A coalition of prominent medical and health organizations, 21 state attorneys general, and environmental groups moved swiftly and filed separate lawsuits in the D.C. Circuit, arguing the mercury rollback was unlawful. The American Academy of Pediatrics, the American Lung Association, the American Public Health Association, and Physicians for Social Responsibility—all plaintiffs in the lawsuit—stated that without the 2024 Mercury and Air Toxics Standards, harms to children’s brain development will increase and risks of respiratory conditions like asthma will become worse.

For parents like myself, this is not an abstract regulatory dispute about what makes good environmental policy. This is about protecting our children and communities living close to these coal plants (knowing very well that mercury laden air pollution travels).

Understanding what is at stake requires understanding the pathway of exposure. Coal-fired power plants are the largest single source of mercury air emissions in the United States which is why the regulations in 2024 targeted a reduction across mercury, arsenic, lead and nickel. Atmospheric deposition is the primary source of mercury to most aquatic ecosystems, and emissions from coal-fired power plants are the largest source of mercury to the atmosphere.

Once emitted, mercury travels through the air—sometimes hundreds of miles—before being deposited in water and soil. In aquatic sediments, bacteria convert inorganic mercury into methylmercury, the organic form that is far more toxic and biologically persistent. Methylmercury levels in predatory fish are typically more than one million times higher than methylmercury levels in the water those fish inhabit, the result of bioaccumulation compounding up every level of the food chain. The fish people eat, particularly large predatory freshwater species like bass, pike, and walleye, are the primary vehicle of human exposure.

This is a concept you may remember learning in high school science class, called bioaccumulation. The same concept I discuss in my book CLEANING HOUSE as it relates to how toxic flame retardants travel from our couches into the environment and build up in marine life like the blubber of whales.

Due to decades of mercury deposition, mercury contamination in freshwater fish is widespread and significant enough to warrant fish consumption advisories in all 50 states. Mercury contamination therefore is a contamination issue for generations. It is (was) the proactive and comprehensive nature of the ‘24 law that helps reduce future mercury emissions across various exposure pathways.

The geographic hotspots for methylmercury in fish track closely with coal plant density and the presence of wetland ecosystems that accelerate methylation. A 2014 USGS national survey found that methylmercury concentrations in fish were typically highest in wetland areas including the coastal plain streams in the Southeast, a region heavily populated by coal plants and subsistence fishing communities. The Midwest and Appalachia, also home to aging coal infrastructure, face elevated risk from both direct atmospheric deposition and contaminated freshwater fisheries.

Communities near plants—disproportionately low-income communities of color—face the highest and most direct exposures.

The biological mechanism of methylmercury’s harm to developing children is well established in the peer-reviewed literature. Mercury is highly toxic and may negatively influence neurodevelopment because it can freely cross the placenta and accumulate in the fetal brain. Once it crosses the placental barrier, it becomes concentrated in fetal neural tissue during critical windows of brain development.

A comprehensive 2025 overview of systematic reviews—synthesizing 29 reviews published between 2018 and 2024—concluded that higher mercury exposure during pregnancy may be associated with higher risk of birth defects, preterm birth, ADHD, and low birth weight. The scientific consensus also found that during childhood, higher exposure was associated with increased risk of ADHD and adverse neurodevelopment.

It should be noted that we must tread lightly when looking at the environmental intersections with neurotypes like ADHD and autism, more on that here.

The consequences for cognitive development can persist into adulthood. Research led by Harvard toxicologist Elsie Sunderland found that exposures to methylmercury are associated with neurocognitive deficits, and the epidemiological literature shows this does persist into adulthood, while mercury exposure in adults is independently linked to cardiovascular disease and impairments in fine motor function and verbal memory.

The original 2012 MATS rules produced one of the most successful regulatory outcomes in American environmental health history. Before MATS was established in 2012, there were no federal limits on how much mercury and toxic air pollution coal and oil-fired power plants could emit.

The standards led to a 90% reduction in mercury emissions and an 80% drop in other toxic metals, and helped save up to 11,000 lives each year.

The 2024 updates that have now been repealed went further, tightening limits on lignite coal plants by 70% and adding continuous monitoring requirements so communities could know in real time what their local plants were emitting. That monitoring requirement has also been eliminated. According to Earthjustice, the EPA also eliminated a requirement that power plants install cost-effective systems to continuously monitor the amount of pollution they emit—depriving communities of a powerful tool for ensuring power plants comply with air pollution standards.

Most power plants already had the technology in place to meet the updated 2024 standards. This rollback was not a response to technological impossibility, it was a deliberate choice.

• If you are pregnant or planning to become pregnant, or if you have young children, the practical guidance has not changed—but the urgency has increased. The FDA and EPA recommend that pregnant women, women of childbearing age, and young children avoid high-mercury fish species: shark, swordfish, king mackerel, tilefish, bigeye tuna, orange roughy, and marlin. Lower-mercury options: salmon, sardines, trout, herring, tilapia, and canned light tuna, are safe to eat in recommended amounts and nutritionally important. I love the SeaFood Watch app to make this easy.
  

• Check your state’s current freshwater fish advisories before eating locally caught fish. All 50 states maintain advisory systems; those in the Southeast, Midwest, and near coal plant corridors warrant particular attention. Your state’s environmental or health department maintains an up-to-date advisory list.
  

• Watch the litigation. The lawsuits filed by 21 state attorneys general and the coalition of health organizations represent the most direct near-term mechanism for restoring these protections. The D.C. Circuit has heard—and ruled favorably on—similar Clean Air Act challenges before.
  

• Sign up for this publication The Environmental Health Report to be the first to receive my non-partisan voter guide heading into the Midterm Elections: Cleaning House at the Ballot Box.
  

• Call your members of Congress and tell them NO MORE roll backs to toxic chemical and environmental laws.

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