May 3, 2023
Toxic Coal Ash in Minnesota: 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. Minnesota has 35 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.
17 Regulated Coal Ash Disposal Sites in Minnesota
Minnesota utilities operate 17 federally regulated coal ash ponds and landfills containing more than 37 million cubic yards of toxic waste at seven coal plants.
These dumps have already caused significant groundwater contamination.
Plant operators have not yet completed a comprehensive cleanup to restore water resources, despite the legal requirement to do so.
| Black Dog | Burnsville | Xcel Energy | 3 unlined ponds | Not evaluated |
| Clay Boswell | Cohasset | Minnesota Power | 4 unlined ponds, 1 landfill | Arsenic (x3), Boron (x3), Molybdenum (x1), Sulfate (x3) |
| General Waste Industrial Landfill | Keewatin | General Waste & Recycling, LLC | 1 landfill | Sulfate (x4) |
| Fox Lake Generating Station | Sherburn | Interstate Power and Light Company | 1 unlined pond | Not evaluated |
| Hoot Lake | Fergus Falls | Otter Tail Power Company | 1 landfill | Unsafe levels of radium and cobalt* |
| Northeast Power Station | Austin | Austin Utilities | 1 unlined pond | Not evaluated |
| Sherburne County Generating Plant | Becker | Xcel Energy | 1 lined pond, 1 unlined pond, 1 landfill | Unsafe levels of nitrate, sulfate, arsenic, cobalt, selenium, lead, molybdenum, antimony, and cadmium* |
| Syl Laskin | Hoyt Lakes | Minnesota Power | 1 lined pond | Unsafe levels of sulfate, boron, cobalt, and lithiuma |
| Taconite Harbor | Schroeder | Minnesota Power | 1 landfill | No data on constituents exceeding standards |
* Based on industry monitoring data. See Ashtracker.
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 Alabama and throughout the U.S., see Mapping the Coal Ash Contamination.
18 Coal Ash Legacy Ponds and Inactive Landfills in Minnesota
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.
Minnesota also hosts at least 18 inactive coal ash landfills and legacy ponds at six coal plants. The exact number is unknown because utilities were not required to publicly report these unregulated dumps.
Evidence has already shown that coal ash has contaminated groundwater at some of these sites, but there are no federal monitoring or cleanup requirements.
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.
| Allen S King | Bayport | Northern States Power Co | 2 | 1 | Unknown |
| Black Dog | Burnsville | Xcel Energy | 0 | 1 | Unknown |
| Clay Boswell | Cohasset | Minnesota Power | 0 | 2 | Yes – Industry data |
| Hoot Lake | Fergus Falls | Otter Tail Power Company | 0 | 7 | Yes – Industry data |
| Northeast Power Station | Austin | Austin Utilities | 0 | 1 | Unknown |
| Riverside MN | Minneapolis | Northern States Power Co | 1 | 0 | Unknown |
| Taconite Harbor | Schroeder | Minnesota Power | 0 | 4 | Unknown |
Clay Boswell's evidence of site contamination: Data derived from the utilities’ publicly accessible CCR Compliance Data and Information websites, and exceedances were calculated by Environmental Integrity Project
Hoot Lake's evidence of site contamination: Based on industry monitoring data. See Ashtracker.
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, Senior Legislative Counsel, Earthjustice, csantillana@earthjustice.org
Lisa Evans, Senior Counsel, Earthjustice, levans@earthjustice.org.
More on Coal Ash
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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