Toxic Coal Ash Used in Neighborhoods Poses Health Risks Even Decades Later

Coal ash is the toxic waste left behind when power plants burn coal for energy; it is a mix of carcinogens, neurotoxins, heavy and radioactive metals, and other hazardous pollutants. Yet for decades, utilities have encouraged the use of toxic coal ash as a substitute for soil in construction and landscaping, claiming it was safe. Coal ash has been used as fill in neighborhoods, backyards, parks, and public areas, including playgrounds and school grounds.The Environmental Protection Agency (EPA) assessed the risk when coal ash is mixed with clean surface soil in residential areas and found that even a small amount of coal ash can result in elevated cancerand other health risks.

Coal ash remains one of the largest toxic industrial waste streams in the U.S. but it was not regulated by the EPA until 2015. Earthjustice fought for years to secure necessary safeguards for coal ash storage and disposal at coal-fired power plants but the EPA lacks effective protections for use of this toxic waste as construction and landscaping fill. The placement of coal ash on the ground in quantities less than 12,400 tons (equivalent to a football field piled six-feet high) is completely unregulated. This has allowed utilities to avoid disposal costs by selling their coal ash to construction companies and landscapers as a substitute for clean fill. Immense volumes of coal ash have historically been used as fill in the U.S. The industry-led American Coal Ash Association admits that nearly 190 million tons of coal ash was “beneficially” used as structural fill between 1980 and 2019. But the use of coal ash as fill was seldom tracked by states, so where it was used remains largely unknown.

What we do know is that utilities promoted coal ash use wherever fill was needed, including on playgrounds, schools, hospitals, and residential properties. Few states regulate its placement, so coal ash was placed near drinking water sources, homes, and sensitive ecosystems. The EPA must strictly regulate the use of coal ash as a substitute for clean fill and investigate where it was placed.

Coal ash used as fill contaminates water and soil

When coal ash is placed on the ground, dangerous pollutants such as arsenic, boron, cobalt, lithium, and mercury will leak into the groundwater. To date, the EPA has documented 26 sites where ash used as fill caused significant water contamination. Examples of devastating damage include:

• Town of Pines, IN, where widespread coal ash fill contaminated the town’s drinking water wells. The EPA declared Town of Pines a Superfund site in 2001. Cleanup is still ongoing, 23 years later.
• Gambrills, MD, where coal ash fill contaminated residential drinking water wells in 2006 after Constellation Energy used more than 4 million pounds of ash to fill a nearby quarry. Drinking water wells were contaminated with high levels of heavy metals, including arsenic, cadmium and lead.
• Battlefield Golf Course, Chesapeake, VA, where 1.5 million tons of coal ash from Dominion Energy was used to create a golf course. The coal ash quickly contaminated the water of nearby residents with arsenic, boron, and other harmful chemicals.

Use of coal ash as fill also contaminates soil with dangerous levels of hazardous chemicals. When the coal ash is left uncovered, small particulates from coal ash can be inhaled and lodge in lung tissue, causing lung damage and potentially cancer. Examples of dangerous uncovered fill sites include:

• Town of Pines, IN, where arsenic levels in surface soil at a public playground reached 450 parts per million and residential soil contained 888 ppm of arsenic, which more than 1300 times the EPA’s safe level for residential soil.
• Mooresville, NC, where more than 1 million tons of coal ash from Duke Energy’s Marshall Steam Plant was used as a substitute for clean soil between 1996-2010 on residential properties, a school, roads, and commercial properties. Coal ash exposed near a daycare center was contaminated with radium above health standards and arsenic 18 times above background levels.
• Southeastern Puerto Rico, where from 2004 to 2012, more than 2 million tons of coal ash from the AES Guayama Plant were used at dozens of sites, including housing, hospital, and road projects in an environmental justice community. Most sites are located directly above the South Coast Aquifer in the vicinity of public supply water wells, and in some cases ash was placed directly in the aquifer. At dozens of sites, coal ash remains uncovered and close to homes, parks, and schools.

EPA’s new findings of risk from coal ash fill

Structural fills can contaminate groundwater with heavy metals in the same manner as coal ash landfills and ponds, which, according to industry data, are contaminating groundwater at nearly every U.S. coal plant. Arsenic is the most prevalent coal ash pollutant found in contaminated water. In a new risk assessment from May 2024, the EPA quantified for the first time high risks from exposure to arsenic and radioactivity at coal ash fill sites. First, the EPA found that even smaller fills (1 – 74,800 tons) can contaminate millions of gallons of groundwater with arsenic. This is especially concerning given that the EPA’s draft Integrated Risk Information System (IRIS) Toxicological Review of Inorganic Arsenic from October 2023 proposed raising the cancer potency of arsenic by 35 times. In addition, the toxicological review found increased risk of heart disease from arsenic ingestion and recommended that the safe daily lifetime dose be 10 times lower than the current value. These findings indicate serious harm from exposure to low levels of arsenic, which increases the risk from exposure to coal ash used as fill.

The EPA’s 2024 risk assessment also examined risks posed by radioactivity in coal ash fill for the first time. Coal ash contains radioactive elements, or radionuclides, that release radiation into the environment as they decay. The EPA found that fills located in residential areas can pose a cancer risk by incidental ingestion of heavy metals in the ash or by direct exposure to radiation released from the ash. These risks are reduced when a thick layer of clean soil is used to separate ash from residents or recreators. But this is not often the practice where coal ash is used as fill. The EPA assessed the risk when coal ash is mixed with clean surface soil in residential areas and found that even a small amount of coal ash can result in elevated cancer risk. If the coal ash has higher than average levels of radionuclides or arsenic, EPA estimates that 1 in 10,000 cancer risk would occur at 11% and 33% mixing for radionuclides and arsenic, respectively. If the coal ash has average concentrations of radionuclides, 1 in 10,000 cancer risk is estimated to occur at 21% mixing.

Stop coal ash fill from harming our health and environment

It is the EPA’s duty to protect communities from the unregulated use of toxic coal ash near their homes, schools, parks, and water supplies. The EPA must promptly take the following actions:

• Quantify the full range of health risks posed by coal ash used as structural fill, including the new risk identified from radiation;
• Investigate known areas where coal ash fill has been placed near residences and require cleanup;
• Initiate a rulemaking to strictly regulate the use of coal ash as structural fill;
• Promptly issue a public advisory recommending that coal ash fill in residential areas be immediately terminated pending a final rulemaking.

The current EPA Rule lacks protective standards

Because of the high risk of harm from the release of hazardous substances, the use of coal ash fill without protective safeguards should be prohibited. Any placement of coal ash on land requires the certainty of long-term monitoring and maintenance, as well as location restrictions, to ensure the buried ash is not leaking, uncovered, abandoned, or placed near water supplies. Most landowners are poorly equipped, both technically and financially, to carry out these challenges. As a result, landowners and the surrounding communities, may be harmed by the presence of coal ash used as fill. Mismanagement has resulted in significant harm to human health and the environment, as evidenced by the many fill sites where covers have eroded, water has been contaminated, and sites have been abandoned. This damage has occurred across the U.S., from Indiana to Puerto Rico. Coal ash fill sites are an environmental justice issue, as these sites occur most often in areas where residents are low income or people of color.

The EPA must treat the placement of coal ash on land, in any volume or location, as the dangerous disposal of a hazardous substance, known to have a high likelihood of creating highly toxic air and water pollution and presenting substantial risk of direct contact and ingestion.