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Map Feature Coal Ash Contaminated Sites & Hazard Dams

Coal ash is the toxic waste formed from burning coal in power plants to make electricity. The second largest industrial waste stream in the U.S., coal ash is linked to the country's four leading causes of death: heart disease, cancer, respiratory diseases and stroke.

Hundreds of contaminated sites and spills have been documented among the 1,400+ coal ash waste dumps across the country.


Contamination & spills (Known* cases). Coal combustion waste sites have contaminated groundwater, wetlands, and rivers.


High (81 dams) & Significant (250 dams) hazard coal ash ponds. The hazard ratings refer to the potential for loss of life or damage if there is a dam failure.

Map of coal ash-contaminated sites and spills, and significant and high hazard dams.

Spotlight State Fact Sheets:

Contaminated Site & Spill
Contaminated Site
High / High* Hazard Dam
Significant Hazard Dam

About the Contaminated Sites & Spills

* The 208 known cases of documented water contamination are likely to be only a small percentage of the coal ash-contaminated sites in the United States (last updated: February 2014). Most coal ash landfills and ponds do not conduct monitoring, so the majority of water contamination goes undetected.

According to U.S. EPA, there are over 1,000 operating coal ash landfills and ponds and many hundreds of "retired" coal ash disposal sites.

Contamination of groundwater, wetlands, creeks, or rivers could easily have been prevented with sensible safeguards such as phasing out leak-prone ash ponds and requiring the use of synthetic liners and leachate collection systems. Yet, ash and other coal combustion wastes are not subject to federal regulations that require these simple safeguards.

View contaminated sites & spills on a larger map.

Source documentation:

About the Hazard Dams

The U.S. EPA rates coal ash ponds according to a National Inventory of Dams criteria that categorizes the ponds by the damage that would occur in the event of a dam failure.

Coal ash dams are usually built from a combination of soil and ash and often impound millions of tons of toxic coal ash and wastewater. The majority are over 40 years old, and most do not have monitoring to detect leaks of toxic pollutants.

There are 331 High and Significant hazard coal ash ponds in the United States. (last updated: December 2014.)

View hazard dams on a larger map.

The NID hazard potential ratings refer to the potential for loss of life or damage if there is a dam failure:

  • High / High* Hazard: Failure or mis-operation of these dams will probably cause loss of human life. (Designations of High* are based on state determinations. EPA considers the hazard potential of these dams to be Significant.)
  • Significant Hazard: Failure or mis-operation of these dams results in no probable loss of human life, but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns.

For detailed information on the sites and state overviews, refer to the state fact sheets below.

For more information on coal ash ponds and landfills in the southeast, visit Southeast Coal Ash Waste, a website by Earthjustice's coalition partners at the Southern Alliance for Clean Energy.

See the latest news from Earthjustice on coal ash.

How Safe is Your State?

In response to Freedom of Information Act requests filed by Earthjustice and our partners, the EPA has revealed the existence of more than 1,400 coal ash dump sites across the country. Fact sheets include detailed analysis based on data available and full citations for statistics. Download fact sheets: