The Mercury Rule Will Save Even More Money Than The EPA Thought

Mercury levels can be decreased with regulation, researchers found. CREDIT: AP PHOTO/CHARLIE NEIBERGALL
Mercury levels can be decreased with regulation, researchers found. CREDIT: AP PHOTO/CHARLIE NEIBERGALL

The Environmental Protection Agency’s so-called Mercury Rule, which curbs mercury released from power plants, offers tens of billions of dollars in health benefits, according to a new review of research from the Harvard School of Engineering and Applied Science.

Findings such as these could be critical to the EPA’s successful defense of the rule and the ultimate goal of reducing Americans’ exposure to mercury. (If you have ever been told not to eat fish out of certain streams, mercury poisoning is likely the reason.)

Last year, the Supreme Court determined that the agency illegally failed to consider how costly it would be to regulate mercury from coal and oil-fired plants, which contribute half of the United States’ mercury emissions. The pro-industry ruling, a 5–4 decision penned by the late Justice Antonin Scalia, sent the regulation back down to the D.C Circuit Court for consideration.

The EPA has said it will submit a cost analysis by April 16, at which point the court could invalidate the rule or find that repealing it would cause more harm than good. The rule has been in effect while the consideration goes forward.


The review of recent scientific literature, published in Environmental Science and Technology, found that the benefits of the rule are “easily in the tens of billions” of dollars. The EPA didn’t even consider cardiovascular health benefits, the scientists said, which have more recently been tied to mercury exposure. Furthermore, the EPA underestimated how effectively reducing mercury emissions from coal-fired power plants would reduce mercury exposure in the general public.

Methylmercury, the compound that comes from power plants, is a powerful neurotoxin that can affect coordination, impair speech and hearing, cause muscle weakness, and degrade vision. Exposure to methylmercury in utero and for infants and small children can have significant long term health impacts, including cognitive and fine motor impairments.

In its initial estimates, the EPA said the Mercury Rule would have $4 million to $6 million in benefits. In its analysis of monetary benefits, the agency looked at an extremely narrow set of benefits: health impacts to the children of recreational freshwater fishermen, the scientists noted. In reality, a wide swath of the American public will likely benefit from a reduction in mercury emissions.

In their literature review, the authors also found that regional and local efforts have been “better than expected” at reducing mercury exposure. Those results were not available to the EPA during its initial analysis of the rule’s impact.

Last month, the authors submitted their research to the D.C. Circuit Court, which asked for the review.

“The Clean Air Act has been one of our country’s greatest successes stories,” Shaun Goho, a co-author of the paper from the the Emmett Environmental Law and Policy Clinic at Harvard Law School, said in a statement. “Yet, when it comes to mercury and other toxic air pollutants, only one major source of emissions has escaped regulation for the last 25 years: coal-fired power plants. Power plants are the number one source of mercury emissions in the United States and limits on those emissions are long overdue.”


The Mercury Rule is not the only EPA action on cleaning up power plants that is undergoing a court challenge. Last week, the Supreme Court issued a stay of the Clean Power Plan, which seeks to curb carbon emissions.