May 4, 2023
Toxic Coal Ash in Wisconsin: 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. Wisconsin has 52 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.
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.
20 Regulated Coal Ash Disposal Sites in Wisconsin*
Wisconsin utilities operate 20 federally regulated coal ash ponds and landfills, containing more than 5.9 million cubic yards of toxic waste at eight coal plants.
Coal ash has caused significant groundwater contamination at nearly all the state’s regulated dumpsites according to utility data reported in 2017.
To date, however, few Wisconsin plants are even monitoring groundwater for heavy metals.
It is likely that unregulated legacy ash on the power plant sites allows Wisconsin utilities to avoid the strict monitoring and cleanup requirements of the Coal Ash Rule.
* Northern States Power Co’s Bay Front Plant, located in Ashland, WI, operates inactive coal ash ponds at the facility according to historical reporting to EPA, but the owners have not created a CCR Rule Compliance Data and Information website nor have they complied with the CCR rule’s requirements that apply to this pond, including groundwater monitoring, closure, and corrective action.
| Columbia | Pardeville | WI Power & Light | 2 unlined ponds, 3 landfills | Arsenic (x2), Boron (x1), Molybdenum (x2) |
| Dairyland Power | Alma | Dairyland Power | 1 landfill | No contaminants exceeding federal standards |
| Edgewater | Sheboygan | WI Power & Light | 4 unlined ponds, 1 landfill | Arsenic (x2), Boron (x5), Cobalt (x1), Lithium (x1), Molybdenum (x55) |
| Nelson Dewey | Cassville | WI Power & Light | 2 unlined ponds | Boron (x2), Molybdenum (x1), Thallium (x1) |
| Oak Creek | Caledonia | We Energies | 1 landfill | Molybdenum (x1) |
| Pleasant Prairie | Pleasant Prairie | WI Public Service | 1 landfill | Molybdenum (x4) |
| Weston | Rothschild | WI Public Service | 4 lined ponds, 1 landfill | Cobalt (x2) |
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 Wisconsin, see Mapping the Coal Ash Contamination.
32 Coal Ash Legacy Ponds and Inactive Landfills in Wisconsin
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.
Wisconsin hosts at least 32 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.
| Alma | Alma | Dairyland Power | 1 | 3 | Yes – EPA damage case |
| Bay Front | Ashland | Xcel Energy/No. States Power Co- MN | 0 | 1 | No data |
| Ceder Sauk Landfill (Received ash from Port Washington Plant) | Saukville | WI Electric Power Co | 0 | 1 | Yes – EPA damage case |
| Edgewater | Sheboygan | WI Power & Light | 0 | 1 | Yes – EPA damage case |
| EJ Stoneman | Cassville | Dairyland Power | 1 | 0 | Yes – EPA damage case |
| Genoa | Genoa | Dairyland Power | 2 | 2 | No data |
| Highway 32 Landfill | Ozaukee Co | WEPCO | 0 | 1 | Yes – EPA damage case |
| Highway 59 (Received ash from Valley Plant) | Waukesha | We Energies | 0 | 1 | Yes – EPA damage case |
| John P Madgett / Dairyland Power | Alma | Dairyland Power | 0 | 2 | Yes – EPA damage case |
| Lemberger Landfill | Whiteclaw | Unknown | 0 | 1 | Yes – EPA damage case |
| Nelson Dewey | Cassville | WI Power & Light | 0 | 1 | Yes—EPA damage case |
| Oak Creek | Caledonia | We Energies | 0 | 2 | Yes – EPA damage case |
| Pulliam | Green Bay | WI Public Service | 1 | 1 | Yes – EPA damage case |
| Rock River | Beloit | WI Power & Light Co | 4 | 0 | Yes – EPA damage case |
| Valley | Milwaukee | WI Electric Power Co | 0 | 3 | No data |
| Weston | Rothschild | WI Public Service | 0 | 2 | Yes – EPA damage case |
| Woodfield Landfill (Received ash from Bay Front Plant) | Bayfield Co. | Northern States Power | 0 | 1 | Yes – EPA damage case |
The retired Alma plant and the current John P Madgett (Dairyland Power) plant are directly adjacent to one another. The EPA damage case is technically for the Alma plant but is listed for John P Madgett as well given their proximity.
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.
“EPA damage case” denotes a site where US EPA has found documented groundwater contamination from coal ash.
For More Information
Christine Santillana, Legislative Counsel, Earthjustice, csantillana@earthjustice.org
Lisa Evans, Senior Counsel, Earthjustice, levans@earthjustice.org.
More on Coal Ash in Wisconsin
Coal Ash in States, Territories, Regions
Puerto Rico (En Español)
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.
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