You can read the full EPA draft risk assessment report that address more than just structural fill (82 pages) or excerpts that are specific to that use (10 pages). We’ve annotated the second document to help readers understand what it means.
The black dirt on the steep slope of an overgrown knoll of trash overlooking the Bolin Creek greenway in Chapel Hill is, in fact, not dirt.
It’s coal ash, fully exposed to the elements. On this windy winter morning, it’s hard to know if ash particles are hitchhiking on the breeze, but to stand downwind elicits a sense of unease.
Coal ash could increase a person’s cancer risk significantly more than previously estimated, according to a recent EPA report, raising questions about the safety of places where ash has been used as structural fill.
This is especially true where the ash is visible, like the mound along the Bolin Creek greenway. Like in Mooresville, where ash has escaped a sinkhole in a commercial parking lot, and protruded through crumbling asphalt at Lake Norman High School. Like in Weldon, where state inspectors found swaths of exposed ash at an abandoned sawmill.
At least 8.85 million tons of coal ash have been legally used as fill at a minimum of 72 locations in North Carolina, state records show. However, because the state did not require documentation of structural fill sites until 1994, the number is likely far higher.
Nationwide, the American Coal Ash Association estimates that a total of 180 million tons of the material have been used in fill projects throughout the U.S. since 1980.
The material was commonly used as a cheap way to undergird parking lots, buildings, runways and road beds, reinforce berms at rifle ranges, and even enhance the soil on farm fields. It originated at coal-fired power plants, including Duke Energy, Cogentrix, Roanoke Valley, and even smaller facilities that served textile mills and universities.
As long as the ash is adequately shielded with a barrier, such as concrete, asphalt or thick layers of dirt, then it is unlikely people would be exposed to the contaminants in soil, the EPA wrote. (When those contaminants reach groundwater or surface water, they can travel and enter the drinking water supply, presenting additional hazards.)
But when that barrier is breached and the material is exposed, the arsenic and radiation can be released.
Late last year, the EPA published a draft risk assessment of coal ash residuals, also known as CCRs. The agency found that even low levels of arsenic and gamma radiation, which are present in CCRs, drive an increased cancer risk. Although the EPA limited its scope of the risk assessment to fill used on land at electric power plants, its conclusions can be applied to similar sites elsewhere.
And it doesn’t take much exposed ash to be hazardous. The EPA found that there is an elevated cancer risk even when ash composes of only 1% to 2% of the soil mixture. When more ash is present, as little as 8% of the soil mixture, then cancer risks are high enough to trigger EPA regulations.
The cancer potency of arsenic is 35 times higher than previously acknowledged, according to the previous EPA risk assessment. Depending on the level of exposure, people can develop other health problems unrelated to cancer; high blood levels of arsenic and cadmium have been linked to a greater risk of heart disease and stroke.
Earthjustice, a national environmental law firm, and 150 public interest groups sent a letter last month to the EPA asking the agency to ban the use of coal ash in structural fill. “These findings are alarming because coal ash used as fill is often not diluted nor covered with soil to shield its radioactivity,” the letter reads.
State Department of Environmental Quality spokeswoman Melody Foote said the agency is reviewing the EPA’s draft assessment and proposed rule changes.
Duke Energy disagreed with the EPA’s report. “The findings in EPA’s draft risk assessment are not reflective of real-world conditions,” Duke Energy spokesman Bill Norton said. “Rather, EPA made unreasonable assumptions in the absence of robust scientific data. The extremely small amount of radiation from coal ash is similar to the background radiation we experience every day from natural soils.”
In North Carolina, ash is rarely used as fill anymore because of public concerns about its safety, particularly after Duke Energy’s massive coal ash spill into the Dan River in 2014. Norton said the utility no longer provides ash for structural fill in North Carolina, which state records confirm.
However, millions of tons of ash remain, some of it securely encapsulated — and some of it not.
A nagging problem in Chapel Hill
Since 1982, the Chapel Hill police department at 828 Martin Luther King Blvd., sat atop 46,000 tons of ash that had originated at the UNC-Chapel Hill power plant. Over time, the slopes eroded, and in 2013, released ash and contaminated soil and groundwater adjacent to Bolin Creek. The town removed the exposed ash and installed a “super silt” fence to prevent material from entering the adjacent greenway. However, exposed ash is still visible on the slopes.
When the police department announced it would move, town officials originally planned to build affordable housing on the site, but subsequently retreated because of public outcry. The latest proposal includes a variety of uses: a municipal services center, office, retail, bus infrastructure and public green space.
Yet as early as 1994, state environmental regulators advised against using coal ash as fill under public green spaces. Referring to an unrelated site, DEQ wrote at the time that it “does not agree on including areas of high intense public uses such as parks, golf courses and ball fields for using structural fills.”
Now the EPA’s draft risk assessment could further alter the cleanup plans.
Chapel Hill Town Manager Chris Blue told Newsline that town officials are “gathering information” about the EPA’s recent draft risk assessment. “We will continue to work with both the EPA and DEQ to meet their requirements for any additional remediation or redevelopment of the property.”
Nick Torrey is an attorney with the Southern Environmental Law Center. The SELC is representing Friends of Bolin Creek, which opposed building residences atop the ash.
“I think they need to go back to the drawing board and recalculate the risk,” Torrey said. “The cleanup will require doing a lot more. The eroding slope needs to go, and all areas with unacceptable health risks need to be removed.”
- Cherry Point Marine Corps Base, Craven County, 12,300 tons*, on-site coal-fired heating plant, impact berm for the use of live rifle target practice
- Kilpatrick Farms, Duplin County, 23,000 tons, Cogentrix Energy, under concrete floors of hog production houses
- Southport Gymnasium, Brunswick County, 430 tons, Cogentrix Energy, under gymnasium
- O.N. Vaughan property, Halifax County, 49,000 tons, Roanoke Valley Energy, conversion of an old mine to pasture land
- Interchange of I-95 and NC Highway 125, Halifax County, 3,116 tons, Roanoke Valley Energy, roadway embankment
- Jake Alexander Boulevard Extension, Rowan County, 11,900 tons, road embankment, Fieldcrest-Cannon facility
The town has hired contractors to sample the soil, groundwater and Bolin Creek in order to learn about the nature and extent of the contamination. Soil and groundwater contained levels of 10 chemicals, including arsenic, barium, cadmium, cobalt and manganese, above state standards, public records show.
Contractors, though, did not test for radium, which is radioactive, and known to be present in coal ash. When radium decays, it releases gamma radiation. Exposure to either form can cause cancer.
Foote told Newsline that in 2019 the Chapel Hill Police station was tested for the presence of radon gas, also a byproduct of radium. It was not detected in three of five samples, Foote said. In the remaining two samples, concentrations were well below EPA action levels. As a result, DEQ did not require further sampling for radium.
However, elevated levels of radium were present in the ash itself, independent researchers found. In September 2022, Avner Vengosh, a distinguished professor of environmental science at Duke University, and several colleagues analyzed the chemical composition of eight ash samples from the 828 site. The samples were gathered from the soil surface to 4 feet deep.
They found not only high levels of arsenic in shallow soils, but also Radium-226 and Radium-228 at levels two to four times higher than background levels.
The EPA has concluded that depending on the thickness of the cover, gamma rays can pass through soil and other materials to reach the ground surface where residents are exposed directly to ionizing radiation.
People can breathe the ash particles, which contain arsenic. The ash may become intermingled with surface soils, the EPA wrote, “where residents are exposed through incidental ingestion of soil and dust present outdoors and tracked into the home.”
The town has enrolled the 828 site, as it’s locally known, in the state’s Brownfields program. A Brownfields site is an area that would be difficult to redevelop because of its contamination. Under a Brownfields agreement, the state requires a developer to clean up the site for certain uses; a clean up level for residential development would be more stringent than one for an industrial building. In return, the developer is not liable for the previous contamination and can more easily obtain financing for a project.
Over the past year, Chapel Hill officials have been negotiating the terms of the Brownfields agreement with DEQ; a draft agreement is scheduled to be released this winter for a 30-day public comment period before it’s finalized.
Exposed ash in Mooresville and Weldon, near homes and businesses
There are at least two other structural fill sites in North Carolina where ash is currently exposed, state records show.
More than 769,000 tons of coal ash from Roanoke Valley Energy was used as fill at a now-abandoned sawmill at 514 Mulberry St. in Weldon. The ash was ostensibly to be used as base material for an access road — never built — and a lumber drying yard.
The 25-acre property is less than a quarter mile from private homes, and is near wetlands and Chockoyotte Creek, which feeds the Roanoke River.
In 2019, 2021 and most recently, six months ago, DEQ inspectors found swaths of exposed ash on the unkempt property.
“There are numerous areas of the structural fill showing signs of exposed coal ash,” inspectors wrote last July, adding that “vegetation was too overgrown to safely inspect” those areas.
The property owner, Job Wommack, had been cited by the state three times from 2001 to 2010 for disposing ash outside of the approved area; for disposing of household and construction waste and other debris on top of the ash; and for allowing the site to erode, which released ash when it rained.
Wommack could not be reached at two numbers listed in public documents.
In 2010, DEQ records show the state issued a compliance order that carried a penalty. The case was never resolved.
One of the most problematic structural fill sites in the county is the Tiremasters property at 190 E. Plaza Drive in Mooresville. Because of an improperly installed pipe and culvert system, a sinkhole formed in the parking lot, releasing coal ash into a tributary of Lake Norman. A legal impasse about who is responsible for repairing the damage — the property owners or Duke Energy — has halted work at the site, allowing the ash to travel unabated.
Tiremasters is one of 20 documented structural fill sites in Iredell County, most of them clustered near Mooresville and Duke Energy’s coal-fired Marshall Steam plant.
This is the same area where North Carolina health officials identified statistically higher incidences of papillary thyroid cancer — two to three times greater — than the state average. Radiation is a main risk factor for this type of cancer, followed by age. It is largely a disease of middle age, afflicting primarily women over 50.
But many of the thyroid cancer cases in Iredell County were reported among teenage girls. Although thyroid cancer rates are rising nationwide, it is unusual for young women to develop it.
State health officials have not linked the thyroid cancer cases in Iredell to the ash. Yet many residents, such as Susan Wind, whose daughter developed thyroid cancer when she was 14, attribute the disease’s prevalence to the tons of coal ash used as structural fill. Some of the deposits – on farm fields, as landscaping – weren’t required to be documented, but several longtime residents remember when it was common.
Wind has since moved her family to Florida, where her daughter, now in her early 20s, continues to battle the disease.
Along with Earthjustice, Wind and many North Carolina residents, like Bobby Jones of Goldsboro and Caroline Armijo of Belews Creek, have petitioned the EPA to enact strong federal rules on the disposal of coal ash — rules that would apply to states.
“An action to remedy these hazardous sites and prevent further dangerous use of toxic coal ash is needed because EPA’s current regulation of coal ash fill is grossly inadequate,” Earthjustice wrote. “For larger volumes, the lack of enforceable safeguards and oversight is equally disastrous.”
NC Newsline is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. NC Newsline maintains editorial independence. Contact Editor Rob Schofield for questions: info@ncnewsline.com. Follow NC Newsline on Facebook and Twitter.