Buyers Beware: Coal Ash In Building Products

James Vallette | January 30, 2014 | Materials

Shortly after HBN published this newsletter, the US EPA released a new report, Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard (February 2014). Click here to read Jim Vallette's analysis of this document.

News reports this week are citing two new EPA-funded studies of coal ash as conclusive proof that using coal power plant waste in cement and wallboard poses no risk to human health or the environment.

Industry proponents say these reports prove that there is nothing to fear from using these wastes in building products, and that this practice will be absolved when EPA releases its new coal ash regulations in December.

Buyers Beware. The stakes are high.

The stakes are high for building owners because coal combustion wastes contain numerous hazardous substances including heavy metals such as mercury, arsenic, and cadmium. The hazards associated with coal combustion wastes are passed on to building owners and occupants. If these hazardous substances can be released when wallboard is cut or demolished, or when breaking or grinding concrete, buildings undergoing renovations could become far more hazardous environments than they are now.

The stakes are high for the power plants and product manufacturers too. Unless coal power plant waste is found to be benign when supposedly “encapsulated”[1] in building products such as concrete, wallboard, ceiling tiles and carpet backing, it will soon be subject to far more restrictive — and expensive — hazardous waste regulations than it has in the past.

Industry pressure to clear this hazardous waste for “beneficial reuse” is enormous because it reduces the costs of operating coal burning power plants and of manufacturing products in which this waste replaces costly materials, such as Portland Cement in concrete.

The EPA’s support for “beneficial reuse” has been so enthusiastic that in 2011, its Inspector General told them to stop.

“While it may be widely believed that different risks are imparted from different forms of CCRs [Coal Combustion Residues], EPA did not provide sufficient information to support this belief,” said the IG. The report found that it “did not follow accepted and standard practices in determining that the 15 categories of CCR beneficial uses it promoted through the C2P2 program were safe for those uses.”[2]

The latest studies continue a cozy relationship between EPA and the coal waste generators, and offer no further reassurances of the safety of coal combustion wastes in building products.

The EPA and the industry’s Electric Power Research Institute, which has a clear interest in seeing coal combustion waste diverted from expensive hazardous waste landfills, funded the articles[3] published in the journal Chemosphere. The authors are longtime advocates of the reuse of industrial wastes in construction materials.

While the authors may make a legitimate case for evaluating the groundwater impacts of foundations during the use phase and at the end of life when the products reside in landfills, the conclusions are being read, by some, as an absolution for all coal wastes in all building products under all conditions.

According to Risk Policy Report[4], "The Chemosphere journal articles lead the recycling sources to expect that EPA's reviews of recycling of fly ash in concrete and coal combustion production gypsum in wallboard will be positive.” (emphasis added)

But the studies are limited to concrete. They do not consider wallboard, ceiling tiles, or carpet backings, which are far different materials. The studies only analyze whether heavy metals may leach from concrete on contact with water. They do not take into account other release pathways, such as dust from construction and demolition. Nor do they consider the cumulative impact of loading building interiors’ largest surface areas — walls, ceilings and floors — with heavy metal contaminants where they did not exist before.

As its own Inspector General noted, the burden of proof is on the EPA as well as industry to prove that there are no exposures. We would expect the agency’s review to go beyond old assumptions about “encapsulation” and expand beyond the narrow lens of leachate testing to assess potential exposures to toxic metals in building materials. We remain unconvinced they have done so.


[1] Through our research on building materials for the Pharos Project, HBN researchers often come across terms like “encapsulated,” “bound in a matrix,” and “fully cured.” Manufacturers use these phrases to counter concerns about the presence of toxic ingredients in their products. But we have seen plenty of evidence that people are exposed to these supposedly “inert” products. Semi-volatile organic compounds, like phthalates, migrate from solid materials, like vinyl flooring. External forces wear these products down over time, through abrasion (cleaning), biodegradation, hydrolysis, photolysis, and oxidation. Then there’s the grinding, smashing, and pulverizing during construction and demolition. Ingredients, including non-volatile ones like heavy metals, travel through the air, in dust particles, with which people obviously come into contact. None of these scenarios are considered in the Chemosphere articles.

[2] Office of the Inspector General, EPA Promoted the Use of Coal Ash Products With Incomplete Risk Information, U.S. Environmental Protection Agency, Report No. 11-P-0173, March 23, 2011

[3] The articles are: 1) Kosson, D.S., et al. pH-dependent leaching of constituents of potential concern from concrete materials containing coal combustion fly ash. Chemosphere (2013), and 2) Garrabrants, A.C., et al. Effect of coal combustion fly ash use in concrete on the mass transport release of constituents of potential concern. Chemosphere (2013),

[4] Maria Hegstad, “As EPA Readies Policies, Studies See Few Risks From Encapsulated Coal Ash,” Risk Policy Report, Jan. 28, 2014.