October 14, 2020

Mercury and Air Toxics Standards (MATS)

EPA Announced Mercury and Air Toxics Standards (MATS) for Power Plants

December 21, 2011: EPA press release announced standards to limit mercury, acid gases and other toxic pollution from power plants.
Until now there have been no federal standards that require power plants to limit their emissions of toxic air pollutants like mercury, arsenic and metals – despite the availability of proven control technologies, and the more than 20 years since the 1990 Clean Air Act Amendments passed.

  • The final rule sets standards for all hazardous air pollutants (HAPs) emitted by coal- and oil-fired electric generating units (EGUs) with a capacity of 25 megawatts or greater.
  • All regulated EGUs are considered major under the final rule. EPA did not identify any size, design or engineering distinction between major and area sources.
  • Existing sources generally will have up to 4 years if they need it to comply with MATS.
    • This includes the 3 years provided to all sources by the Clean Air Act. EPAs analysis continues to demonstrate that this will be sufficient time for most, if not all, sources to comply.
    • Under the Clean Air Act, state permitting authorities can also grant an additional year as needed for technology installation. EPA expects this option to be broadly available.
  • EPA issued MATS under a Consent Decree of the D.C. Court of Appeals requiring EPA to issue a proposal by March 16, 2011, and a final rule in December 16, 2011.
  • In 2000, after years of study, EPA issued a scientific and legal determination that it was “appropriate and necessary” to control mercury emissions from power plants. The prior administration finalized a rule to cut mercury pollution from power plants, but the D.C. Circuit struck the rule down and required EPA to develop standards that follow the law and the science in order to protect human health and the environment.

“Gutting” MATS April 16, 2020: EPA press release

Today, the U.S. Environmental Protection Agency (EPA) 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 U.S. Supreme Court decision. The agency also completed the Clean Air Act-required residual risk and technology review (RTR) for MATS. Power plants are already complying with the standards that limit emissions of mercury and other hazardous air pollutants (HAPs), and this final action leaves those emission limits in place and unchanged.

April 2020 Report from earthjustice.org
explaining how the new ruling affects MATS regulation. Wheeler, head of EPA says CBA was wrong and it is no longer necessary to enforce, as we emit only 2% of the world’s mercury form coal. Earth Justice is suing.

Until the Mercury and Air Toxics Standards came on line, they accounted for half of the total man-made emissions of mercury in America and more than half of all arsenic, hydrochloric acid, hydrogen fluoride, and selenium emissions. They are also among the worst emitters of other toxics, including lead (think Flint, Michigan) and chromium (think Erin Brockovich).

Initially established in late 2011 after decades of effort by Earthjustice and others, the Mercury and Air Toxics Standards became the first set of federal regulations to limit mercury and other air toxics emitted by power plants. It also was the first rule to require meaningful reductions of pollution from many older coal plants that had been allowed to dodge pollution control requirements for decades.

“The idea of the Mercury and Air Toxics Standards is to get all the air toxics out of power plants, not just mercury,” says Earthjustice Attorney Jim Pew.
Once the Mercury and Air Toxics Standards was enacted, the worst emitting power plants had to choose between shutting down or installing pollution control equipment such as baghouses and scrubbers. The results were stunning.
Mercury emissions from power plants dropped by 81.7 percent from 2011 through 2017, according a recent analysis by the Center for American Progress. And, contrary to dire predictions by lobbyists for the power industry, power plants are continuing to operate and the lights remain on.
“The reductions were very significant; everything worked very smoothly,” Pew says. “Right now, the rule is working just fine.”


Murray Energy, which claims to be the “largest underground coal mining company in America,” continued to challenge the standards in court. And now with Andrew Wheeler, Murray  Energy’s former lobbyist and current administrator of Trump’s EPA, the agency wants to undermine the Mercury and Air Toxics Standards and let more toxic pollution into the air.


Under Wheeler, the EPA’s new argument is that the Mercury and Air Toxics Standards is not “appropriate” because its costs outweigh its benefits. But that claim rests on some very dodgy accounting.

FIRST, the EPA considers only the benefits of pollution reduction that have been “monetized” — i.e., reduced to a monetary value. For example, the EPA doesn’t count the benefit of eliminating vast quantities of mercury from our air, water, and fish because those benefits have never been monetized. Likewise, the EPA assigns no value at all to eliminating tons of emissions of lead, arsenic, and chromium emitted by power plants. Instead, the EPA’s new analysis considers only the monetized value of the IQ points it anticipates will be lost by children who are exposed to mercury in freshwater fish.

SECOND, the EPA dismisses the value of benefits that have been monetized. It is undisputed that the Mercury and Air Toxics Standards also will eliminate the emissions of thousands of tons of fine particulate matter emissions, along with power plants’ emissions of mercury, lead, and other hazardous air pollutants. The EPA has robust data on the health benefits — and the monetary value — of the reduction of particulate matter emissions. It will prevent:

  • up to 11,000 premature deaths from respiratory and cardiovascular illness;
  • 3,100 emergency room visits for children with asthma;
  • more than 250,000 fewer cases of respiratory symptoms and asthma exacerbation in children;
  • and 4,700 non-fatal heart attacks.

All that adds up monetarily to $90 billion. The total cost of the rule is about $9 billion — dimes to dollars.

Edison Electric Institute, the association that represents all U.S. investor-owned electric companies, and other utilities have written letters to the EPA saying just that.

“They’ve already spent the money to comply, they don’t want a disruption by having the deregulation, and they don’t want the bad actors like Murray Energy to get a competitive advantage from this,” Pew says.

If Wheeler’s proposal could establish dangerous precedent for future regulations. The new rule could create a higher threshold for future regulations by narrowing the range of benefits the agency can consider when devising new rules. This would make it nearly impossible for the EPA to justify new life-saving protections.

“What an amazing effort to snatch defeat from the jaws of victory,” Pew says. “Wheeler’s con game will benefit no one but his former clients and, if successful, it will release tons of toxic pollution into the air and cause thousands of people to die unnecessarily every year.

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