EPA is proposing to weaken the Mercury and Air Toxics Rule. Help stop this by submitting a comment to EPA and sharing your thoughts with your representatives.

Take Action

(1) Submit your Comment to EPA. By April 17th, click here to submit your comment at regulations.gov.

Note: Public comments are important! Federal agencies are required to publish responses to comments and justify their decisions with evidence-based information. If they do not, the comments provide fuel for suits against the agency. Suits in turn result in halting or delaying the rules (in this case their weakening) until a ruling. Comments are also a way to show the public’s support for strong environmental protection.

(2) Share your comment with your members of congress.
Note: Sharing comments with members of congress is working! The new House and members of the Senate are listening to environmental concerns and seeking out environmental information/education almost every day. They are writing letters to EPA protesting its actions. We need to continue to reinforce our priorities and let them know we are behind them.

  • Senator Dianne Feinstein: (415) 393-0707, (310) 914-7300, (202) 224-3841, or email.
  • Senator Kamala Harris: (415) 355-9041, (213) 894-5000, (202) 224-3553, or email.

Find your Representative:

  • Rep. Mark DeSaulnier - 11th district: (510) 620-1000, (202) 225-2095, or email.
  • Rep. Nancy Pelosi - 12th district: (415) 556-4862, (202) 225-4965, or email.
  • Rep. Barbara Lee - 13th district: (510) 763-0370, (202) 225-2661, or email.
  • Rep. Jackie Speier - 14th district: (650) 342-0300, (202) 225-3531, or email.
  • Rep. Eric Swalwell - 15th district: 510-370-3322, 202-225-5065, or email.

Suggested Comment

Note: It is best to personalize or modify the wording if possible. You do not need to be a scientist or expert to submit your comments. Add any personal concerns or experiences you, your family or friends have had. You may also create your own comments using information from the references below.

EPA’s proposal to change the way costs and benefits are calculated to determine protective limits for mercury and air toxics (MATS) emissions contains substantial inaccuracies and omits current financial and scientific information. Based on these limitations, alone, the action should be withdrawn.

EPA has not made clear the need and justification for its current proposal. The science, benefits and costs using current information strongly support the existing standards, and industry has already complied at a much lower cost than originally estimated. The proposal does not protect the public, but appears intended to pave the way for EPA to minimize the benefits of future protections and open the current emission limits to legal challenges. This is inconsistent with the intent of the Clean Air Act (CAA), EPA’s other authorizing statutes and EPA’s role in protecting the public.

EPA disregards the substantial public health benefits of reducing pollutants such as particulate matter (PM) that co-exist with mercury emissions (co-benefits), even though representing co-benefits shows the overall benefits of the protections and have been considered important under republican and democratic presidents since 1981. EPA and federal guidelines support consideration of all identifiable costs and benefits, as consistent with standard accounting practices.

EPA justifies this omission by stating that PM is not the “target” pollutant. However, many hazardous air pollutants, including mercury and almost all other metals, are attached to PM. The controls that reduce mercury and other toxics also reduce PM and the constituents that form PM in the atmosphere. There is a clear relationship between PM, mercury and other toxics, as well as clear and significant health benefits from reducing PM. Including PM also helps industry by allowing them to monitor just PM, rather than several individual pollutants.

In publishing the original MATS rule in 2011-2012, EPA used then-available information to quantify some of the health benefits of reducing mercury and listed additional benefits it could not quantify at the time. This is standard practice. EPA is now omitting these unquantified benefits from its analysis entirely. However, currently available science would allow EPA to quantify a much greater benefit than was possible to calculate in 2011-2012. EPA should include this important information in its analysis to present a complete and accurate accounting of benefits.

For example, air monitoring data shows that limiting mercury has a much greater impact than originally estimated. Recent studies show benefits that are orders of magnitude larger than the estimate EPA is currently using. These studies would allow EPA to more accurately estimate mercury reductions in commercial fish consumed by the public, for example. It would allow EPA to include the benefits to cardiovascular health due to mercury reductions. It would update EPA’s assumptions that a threshold exists for the neurological effects of mercury and allow it to take background exposures into account in assessing additional exposures.

EPA overemphasizes the importance of cost in its proposal, even as the information used to establish the costs is incomplete. The CAA provisions related to the MATS rule do not use cost-benefit analysis as the sole basis for setting an emissions limit. However, if EPA used current cost, science and engineering information in its analysis, it would show that benefits far exceed costs.

For example, the cost of purchasing and operating equipment to comply with the MATS rule was much lower in reality than the estimate EPA used for the 2011-2012 rule. This was due to innovations in control technology and the increased use of less costly natural gas, which did not require the controls. This and other current information should be used to present costs accurately.

EPA’s current proposal is not adequately justified as necessary; it omits best and current science and cost information; and it deviates from standard accounting and procedural practices. For these reasons, EPA’s proposal to withdraw the appropriate and necessary finding, to state that it is not necessary to update the standards, and to request comment on rescinding the rule should be withdrawn in total.


Mercury is Highly Toxic
Mercury causes neurological disorders, cardiovascular harm, endocrine disruption and weakened immune systems. Developing fetuses and children can suffer serious cognitive impairment. When it enters water bodies it accumulates in the food chain, leading to high concentrations in fish. When the fish are consumed by people or wildlife mercury can damage multiple organ systems.

History of Regulation (Abridged)
Coal fired power plants were the biggest emitters of man-made mercury before the MATS rule went into effect, yet they were among the last to be regulated after at least 21 years of delays due to lobbying and suits brought by industry.

In order to regulate air toxics like mercury under the Clean Air Act (CAA), EPA must make the case that it is “appropriate and necessary” to regulate them - an A&N Finding. In 2000 EPA made that determination.

In 2012, EPA published its final Mercury and Air Toxics Standards or “MATS,” which established emission limits at coal- and oil-fired power plants for mercury, acid gases and other metallic pollutants. It also established standards for reducing dioxins and furans.

Industry, states, environmental organizations and public health organizations challenged many aspects of the EPA’s A&N Finding and the final 2012 MATS rule. In 2015, the Supreme Court ruled that the EPA should have considered the cost of compliance as part of its A&N Finding.

In 2015-2016 EPA responded by publishing an analysis of compliance costs showing that they were significantly lower than the health benefits. For every $1 in compliance costs $9 of health benefits would be achieved. As is standard practice, EPA’s analysis quantified the benefits as much as possible but also included a general discussion of benefits for which quantification was not possible.

By 2016 power plants had installed pollution controls. Today the MATS rule has succeeded in reducing mercury emissions nationwide by 85%.

The vast majority of utility companies have said the proposed changes are of little benefit to them, because they have already spent the money to install pollution controls. They have urged the Trump administration to leave the rule in place.

What’s So Important About EPA’s Current Action
According to Janet McCabe, former EPA Acting Assistant Administrator for Air, “There is a likelihood that this rule-making will be the administration’s flagship effort to permanently change the way the federal government considers health benefits.”

The stated purposes of EPA’s current action are (1) to undo the agency’s previous finding that it is appropriate and necessary to regulate mercury emissions; (2) to declare that it is not necessary to update the emissions limits with new science, as EPA is required to do; and (3) to ask for comment on whether the MATS rule should be rescinded.

EPA’s additional unstated purpose is to limit how the agency can regulate emissions in the future in a way that would have far-reaching effects. If this action is successful, it will open a door to rolling these and other standards back or allowing industry to challenge them in court. And it will jeopardize all attempts to set pollution limits in the future.

The key tool EPA is using now to undo the A&N Finding is to change the cost-benefit analysis. Importantly, it is eliminating consideration of the benefits of reducing other pollutants that coexist with mercury emissions. Primarily, this is particulate matter (PM), for which there is a large body of evidence of negative health impacts and robust information to use for cost -benefit analysis. Consideration of the “co-benefits” of reducing “co-pollutants” has been standard practice under EPA and other federal guidelines for decades and it also common sense.

EPA’s proposal goes further by ignoring significant quantified health benefits, all non-quantified benefits (they cannot be measured in dollars) and significant benefits that could be quantified today with new science. Just one of these changes would set a precedent for drastically altering the way the government develops cost-benefit analyses and hinder its ability to maintain current protections and establish future safeguards.

Further tilting its analysis in favor of industry, EPA’s current proposal updates only the health benefits - by deleting them, not by using new science to better quantify them - and maintains virtually the same compliance cost information as EPA’s original findings even though it is now known that the actual costs were much lower.

Using its current biased and faulty analysis, EPA now claims that the costs to industry outweigh the health benefits of regulating mercury. This is not true.

If EPA’s proposal is finalized it sets a precedent that jeopardizes all attempts to set and maintain limits for pollutants in the future.