On August 11, 2025, the Environmental Protection Network submitted comments to EPA opposing their proposed repeal of the 2024 revisions to the Mercury and Air Toxics Standards, which required more stringent mercury emissions for lignite-burning coal plants, lower particulate matter levels for coal-fired power plants, and continuous emissions monitoring. These proposed rollbacks are inconsistent with and do not satisfy Clean Air Act requirements.
EPN’s comments focus on the points summarized below:
- Weaker mercury limits for lignite-fired plants ignores existence of new, affordable control technology
Lignite coal is incredibly dirty, and more lignite fuel must be burned to generate power compared to other types of coal, creating greater and more hazardous emissions.The 2024 update lowered the mercury emission limit from 4.0 lb/TBtu to 1.2 lb/TBtu for lignite-burning plants based on data demonstrating that brominated activated carbon effectively achieves this reduction at lower-than-expected cost without environmental harm. Rolling back to 4.0 lb/TBtu disregards these advances and also fails to consider a feasible intermediate standard across diverse plants, ignoring the requirements of the Clean Air Act. - Removing stricter filterable particulate (fPM) limits and continuous monitoring for non-mercury hazardous metals is inconsistent with the Clean Air Act’s MACT requirements
The proposal would reverse the 2024 fPM standard (0.010 lb/MMBtu) to its previous, less stringent level, and eliminate mandatory PM Continuous Emissions Monitoring Systems (CEMS). In fact, MACT provisions prohibit backsliding and CEMS are cost-effective and critical—providing real-time transparency, performance reliability, and they are already in use by over 80% of plants. - EPA undercounts localized mercury hazards and uses outdated health benchmarks
The 2020 residual risk evaluation used by EPA relies on a 2001 methylmercury reference dose that may underestimate current risks. A recent Harvard study revealed nearby “hotspots” near several lignite plants—accounting for up to 8% of local mercury deposition—that likely exceed health thresholds, disproportionately affecting lower-income communities.