Toxic Coal Ash in Wyoming: Addressing Coal Plants’ Hazardous Legacy

For decades, utilities disposed of coal ash — the hazardous substance left after burning coal for energy — by dumping it in unlined ponds and landfills. Wyoming has 26 coal ash dumpsites.

After years of litigation and grassroots activism, on Apr. 25, 2024, the EPA issued a new rule that will force power plants to finally clean up their toxic coal ash. The EPA extended federal monitoring and cleanup requirements to hundreds of previously excluded older coal ash landfills and ponds that have been leaking toxic pollution into groundwater.

Note: Coal ash dumpsites referenced as “unregulated” throughout this page now are likely subject to federal regulation under the final rulemaking.

Coal ash contains hazardous pollutants including arsenic, boron, cobalt, chromium, lead, lithium, mercury, molybdenum, radium, selenium, and other heavy metals, which have been linked to cancer, heart and thyroid disease, reproductive failure, and neurological harm. In 2023, the EPA acknowledged that coal ash is even more dangerous than previously thought, with levels of arsenic and radiation that pose cancer risks.

Industry’s own data indicate that across the country 91% of coal plants are currently polluting groundwater above federal health standards with toxic pollutants.

Despite EPA’s 2015 Coal Ash Rule, which created the first-ever safeguards for coal ash disposal, many coal ash dumps remained unregulated due to sweeping exemptions for legacy coal ash ponds and inactive landfills. The exempted coal ash dumps are sited disproportionately in low-income communities and communities of color. The EPA extended clean up requirements to hundreds of old coal ash dumps across the country when it issued new regulations in the spring of 2024.

The Naughton Power Plant in Kemmerer, Wyoming,
The Naughton Power Plant in Kemmerer, Wyoming, in 2010. (Nancy Nehring / Getty Images)

Coal ash remains one of our nation’s largest toxic industrial waste streams. U.S. coal plants continue to produce approximately 75 million tons every year.

In 2023, the EPA acknowledged widespread noncompliance with existing coal ash regulations and ramped up enforcement after designating coal ash a national enforcement priority.

Action Needed

The magnitude of harm from recklessly dumped toxic coal ash requires decisive action from federal and state regulators.

  • Utilities must be required to comply with the law and immediately clean up their pollution.
  • EPA and states must act quickly to ensure that utilities leave communities with sites that benefit rather than harm their health, environment, and economic status.
  • EPA must take action to prohibit the use of coal ash as construction fill and make polluters clean up areas where ash was used as fill.
Coal ash dump sites across the United States. Use this map to understand where coal ash might be stored near you and how a given site may be impacted by EPA's expansion of the federal Coal Ash Rule. (Caroline Weinberg / Earthjustice)

18 Regulated Coal Ash Disposal Sites in Wyoming

Wyoming utilities operate 18 federally regulated coal ash ponds and landfills containing more than 53 million cubic yards of toxic waste at four power plants.

Coal ash has caused groundwater contamination at all of Wyoming’s regulated dumpsites.

Some of these dumps are contaminating water at dozens or even hundreds of times the safe levels of certain pollutants.

Two of them, Naughton Power Plant and Jim Bridger Power Plant, are the 3rd and 4th most contaminated coal ash sites in the U.S., respectively.

Despite the serious and widespread water contamination, no Wyoming company, to date, has initiated a plant-wide cleanup to restore groundwater, despite the legal requirement to do so.

Dave Johnston Glen Rock PacifiCorp 1 lined pond, 1 unlined pond, 1 landfill Arsenic (x1), Boron (x4), Cadmium (x2), Cobalt (x3), Lead (x2), Lithium (x1), Molybdenum (x10), Sulfate (x2)
Jim Bridger Point of Rocks PacifiCorp 2 unlined ponds, 1 landfill Antimony (x1), Arsenic (x4), Boron (x9), Cadmium (x3), Cobalt (x92), Fluoride (x3), Lead (x4), Lithium (x164), Molybdenum (x10), Radium 226+228 (x2), Selenium (x85), Sulfate (x125), Thallium (x11)
Laramie River Wheatland Basin Electric Power Coop 5 unlined ponds, 1 landfill Boron (x2), Lithium (x3), Molybdenum (x5), Sulfate (x9)
Naughton Kemmerer PacifiCorp 2 lined ponds, 4 unlined ponds Antimony (x2), Arsenic (x10), Barium (x1), Beryllium (x2), Boron (x16), Cadmium (x2), Chromium (x3), Cobalt (x13), Lead (x16), Lithium (x242), Molybdenum (x3), Radium 226+228 (x1), Selenium (x150), Sulfate (x66), Thallium (x9)

All data on groundwater contamination from coal ash derived from the utilities’ publicly accessible CCR Compliance Data and Information websites, and exceedances were calculated by Environmental Integrity Project.

For more information on regulated coal ash sites in Wyoming, see Mapping the Coal Ash Contamination.

Eight Coal Ash Legacy Ponds and Inactive Landfills in Wyoming

March 2024 Update: The table below underestimates the legacy units that may be regulated by EPA’s upcoming CCR Legacy Pond Rule. Additional legacy units at specific plants may be found in the national map, above.

In addition, Wyoming hosts at least eight inactive coal ash landfills and legacy ponds that escaped federal regulation. The exact number remains unknown because utilities were not required to report these sites.

These dumps are almost certainly contaminating water and threatening health and the environment; however, monitoring data are not currently available for most unregulated sites.

As we anticipate EPA’s proposed rule on legacy ponds and unregulated landfills in May 2023, a concern remains that the agency will not address coal ash that was dumped off site or used as fill.

Jim Bridger Point of Rocks PacifiCorp 0 1 Yes – Industry data
Naughton Kemmerer PacifiCorp 0 1 Yes – Industry data
Osage Osage City of Osage 2 2 Unknown
Wyodak Gillette PacifiCorp 1 1 Unknown

These data were developed by using EPA datasets relied upon in their 2007 and 2014 CCR risk assessments (Human and Ecological Risk Assessment of Coal Combustion Residuals) and comparing those datasets to the universe of regulated units.

“Industry data”: All data on groundwater contamination from coal ash derived from the utilities’ publicly accessible CCR Compliance Data and Information websites, and exceedances were calculated by Environmental Integrity Project.

Earthjustice fights in the courts for a long-term solution to the toxic menace of coal ash. And we act on behalf of dozens of clients and over 100 coalition partners to defeat legislative attempts to subvert federally enforceable safeguards of coal ash.

Earthjustice’s Clean Energy Program uses the power of the law and the strength of partnership to accelerate the transition to 100% clean energy.