Emmett Clinic Files Comments Opposing EPA’s Proposal to Undermine Mercury Standards for Coal-fired Power Plants

April 17, 2019 –The Emmett Environmental Law & Policy Clinic submitted comments today on behalf of a group of leading scientists in opposition to the Environmental Protection Agency’s (EPA) proposal to rescind the finding underlying its regulation of mercury and other toxic air pollutant emissions from coal-fired power plants.  This proposal, if finalized, could lead to the repeal of regulations for the largest source of mercury emissions in the United States.

The Clinic filed the comments on its own behalf as well as on behalf of Elsie Sunderland, Charles Driscoll, Kathy Fallon Lambert, Joel Blum, Celia Chen, David Evers, Philippe Grandjean, Robert Mason, and Noelle Eckley Selin—leading experts in the fields of atmospheric transport, ecosystem fate and effects, bioaccumulation, human exposures, and health outcomes associated with environmental mercury contamination.  Students Nanding Chen and Veronica Wang wrote the comments in collaboration with Emmett Clinic Deputy Director Shaun Goho.

EPA regulates emissions of toxic air pollutants such as mercury under section 112 of the Clean Air Act.  When Congress amended the Clean Air Act in 1990, it directed EPA to set emissions standards for all major sources of 189 toxic air pollutants under a strict timeline.  The one exception was emissions from coal-fired power plants.  Congress in those same 1990 amendments had created the acid rain cap-and-trade program—which applied only to coal-fired power plants—and it was thought that the controls that power plants installed to reduce sulfur dioxide emissions might also reduce emissions of mercury and other air toxics.  Therefore, Congress instructed EPA to determine whether it was “appropriate and necessary” to regulate power plant emissions under section 112 after taking into account the effect of the acid rain program.

In the end, power plants largely complied with the acid rain program by switching to low-sulfur coal, and coal-fired power plants remained the leading source of mercury emissions in the United States.  EPA therefore determined in 2000 that it was appropriate and necessary to regulate toxic air pollutant emissions from power plants.  It confirmed this finding in 2012 and imposed emissions standards at that time.  All coal-fired power plants are now in compliance with those standards.

Nevertheless, EPA has now proposed to reverse its prior findings and conclude that it is not “appropriate” to regulate these emissions.  As our comments explain:

  • EPA’s proposal is based on an eight-year-old analysis which even at that time was incomplete and which underestimated the benefits of regulating power plant mercury emissions.
  • The scientific literature includes significant new evidence of the benefits of regulating power plant mercury emissions, including estimates of those benefits that are orders of magnitude larger than EPA’s.
  • It is now clear that reductions in mercury emissions from power plants result in localized and regional reductions in atmospheric mercury deposition, which amplifies the benefits of decreasing domestic emissions.
  • The entire industry has by now come into compliance with the mercury and air toxics standards. It is therefore no longer necessary to rely on predictions of the compliance costs.  Multiple analyses have estimated that the actual costs of compliance are less than a billion dollars per year compared to the $9.6 billion per year EPA predicted in 2011.
  • Regardless of whether EPA can reverse the appropriate and necessary finding, it does not have the authority to delist power plants or repeal their emissions standards without going through the section 112(c)(9) delisting process

The Clinic’s comments are available here.