US weakens rules on mercury emission from coal plants amid study linking air pollution to COVID-19 death risk
As the coronavirus pandemic rages on, the Donald Trump administration has scrapped regulations requiring coal plants to cut their emissions of mercury and other pollutants that pose significant risks to human health. The move comes even as a recent study found that COVID-19 patients living in areas with high levels of air pollution are more likely to die.
The US Environmental Protection Agency (EPA) has said that it is not “appropriate and necessary” to regulate mercury and other hazardous air pollutants (HAPs) emissions from coal- and oil-fired power plants. The agency argues that a proper consideration of costs under the Clean Air Act demonstrates that the total projected costs of compliance with the MATS rule ($7.4 to $9.6 billion annually) dwarf the monetized HAP benefits of the rule ($4 to $6 million annually).
“After properly evaluating the compliance cost to coal- and oil-fired power plants and the benefits attributable to regulating HAP emissions from these power plants, the agency determined that it is not appropriate and necessary to HAP emissions from power plants under section 112 of the Clean Air Act,” says an EPA statement. It adds, “The EPA acknowledges the existence of HAP benefits that cannot be quantified but concludes that these unquantified HAP benefits cannot reasonably be expected to meaningfully redress the gross disparity between that cost and the monetized HAP benefits.”
The EPA says that it has “corrected flaws” in the 2016 supplemental cost finding for the Mercury and Air Toxics Standards (MATS) for coal- and oil-fired power plants, consistent with a 2015 US Supreme Court decision. The agency says that it has also completed the Clean Air Act-required residual risk and technology review (RTR) for MATS.
Accordingly, the EPA says that power plants are already complying with the standards that limit emissions of mercury and other hazardous air pollutants and this final action leaves those emission limits in place and unchanged. “Under this action, no more mercury will be emitted into the air than before. EPA is following through on the Supreme Court’s direction and correcting the previous Administration’s flawed cost finding in its original rule. Today’s action maintains the mercury emissions standard and meets the statutory obligation to review the adequacy of those standards. This is another example of the EPA, under the Trump Administration, following the law while making reasonable regulatory decisions that are fully protective of the public health and environment,” said EPA Administrator Andrew Wheeler in the statement.
What did a recent study find?
Scientists have found that even a small increase in long-term exposure to PM2.5 before the COVID-19 pandemic leads to a large increase in the COVID-19 death rate.
The researchers from the Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, US, found that an increase of only 1 milligram per cubic meter (μg/m3) in PM2.5 is associated with a 15% increase in the COVID-19 death rate. This indicates that patients living in areas that have high pollution levels are far more likely to die than those in cleaner parts of the country. The results of the study underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis, warn experts.
What do scientists say?
Experts from multiple institutions in the US argue that the likely result of the EPA’s recent announcement will be “weaker and inefficient” regulations on many pollutants, not just mercury and other HAPs.
According to researchers from the Harvard T.H. Chan School of Public Health, coal-fired power plants are the largest source of mercury in the US, accounting for approximately 48% of mercury emissions in 2015. The Mercury and Air Toxics Standards (MATS) were finalized in 2012 to regulate emissions of mercury, acid gases and other hazardous air pollutants (HAPs) from US electric utilities. The 2012 MATS rule was intended to reduce mercury emissions from regulated power plants by 90%, and improve public health.
Explaining the harmful impact of mercury, the researchers say that mercury in the form of methylmercury is a potent neurotoxin. Children exposed to methylmercury during a mother’s pregnancy can experience persistent and lifelong IQ and motor function deficits. In adults, high levels of methylmercury exposure have been associated with adverse cardiovascular effects, including increased risk of fatal heart attacks, say the team. The experts say that the societal costs of neurocognitive deficits associated with total methylmercury exposure in the US were estimated in 2017 to be approximately $4.8 billion per year.
Accordingly, the researchers say that the science is clear and total methylmercury exposure must be taken into account in policy decisions. “The 2012 MATS rule has substantially decreased mercury emissions and improved public health at a much lower cost than anticipated. Yet, EPA continues to rely on the outdated cost and health benefit estimates from the 2011 MATS Regulatory Impact Assessment (RIA) to support its determination,” say experts.
The researchers explain that the “outdated science” that EPA relied on in its current decision assumed that mercury emissions from coal-fired utilities are mainly transported over long distances from the US and that a substantial fraction of mercury in the US comes from international sources.
However, recent research shows that the contribution of US coal-fired power plants to local mercury contamination, particularly in the eastern US, has been markedly underestimated. The scientists explain that mercury controls on US electric utilities have contributed to many emissions reductions and associated environmental and human health improvements in the US. Mercury emissions from US coal-fired power plants, for example, have declined by 85% from 92,000 pounds in 2006 to 14,000 pounds in 2016 since states began setting standards and MATS was introduced in 2011, say experts. Eleven states had implemented mercury emissions standards for power plants before 2011. Concurrent with declines in mercury emissions, mercury levels in the air, water, sediments, loons, freshwater fisheries, and Atlantic Ocean fisheries have decreased appreciably.
“Mercury levels in the blood of women in the U.S. declined by 34% between 2001 and 2010 as mercury levels in some fish decreased, and fish consumption advisories improved. The estimated number of children born in the US each year with prenatal exposure to methylmercury levels that exceed the EPA reference dose has decreased by half from 200,000-400,000 to 100,000-200,000, depending on the measure used,” say experts.
A study published in January this year found that decommissioning of coal-fired power plants in the US has reduced nearby pollution and saved lives. The researchers estimated that between 2005 and 2016, the shift away from coal saved an estimated 26,610 lives and 570 million bushels of crops. The inverse calculation, estimating the damages caused by coal plants left in operation over that same time period, suggests they contributed to 329,417 premature deaths and the loss of 10.2 billion bushels of crops, roughly equivalent to half of year's typical production in the US.
The Harvard scientists argue that the benefits of reducing mercury are much larger than EPA has estimated. “The EPA continues to estimate that the annualized mercury-related health benefits of reducing mercury emissions would be less than $10 million. Recent studies that account for more pathways of methylmercury exposure and additional health effects suggest that the monetized benefits of reducing power plant mercury emissions in the US are likely in the range of several billion dollars per year. "The mercury-related benefits alone of the MATS rule are much larger than EPA has estimated. The actual costs appear to be substantially lower than EPA has projected, and the total monetized benefits across all pollutants far outweigh the cost of the standards,” say scientists.