EPA Finds Coal Fly Ash Safe in Concrete and Gypsum Wallboard
April 2, 2014
A new study supporting the encapsulated use of fly ash in building products is a strong clue as to how EPA might shape pending regulation.
UPDATE 12/20/14: EPA issued its final rules, and as expected, found coal ash safe to use in building materials, and declined to categorize it as a hazardous waste.
As the December 2014 deadline draws near for the U.S. Environmental Protection Agency (EPA) to finalize regulations for—a byproduct of burning coal—the agency released a study offering evidence that the material is safe for use in concrete and gypsum wallboard.
Using a methodology that has become the EPA standard for evaluating products containing fly ash,found that concentrations of 18 constituents of potential concern were higher in cement with fly ash than in portland cement, and the lowest mercury emanation rate measured for gypsum wallboard with fly ash was three times higher than the highest rate for mined gypsum wallboard. However, after an exposure review and screening assessment, the report finds that the increased concentrations are still “below relevant regulatory and health-based benchmarks” and concludes that EPA supports the “beneficial use” of fly ash in these products.
Using fly ash in concrete offsets greenhouse gas emissions, and diverting it for use in other products means less of it is dumped into landfills, where toxic substances may leach into groundwater (see “”). However, some say even the latest EPA study fails to put their concerns over health impacts to rest. In a , The Healthy Building Network warns that the methodology discounts high levels of mercury, was not properly peer reviewed, and fails to investigate exposures that might occur during manufacturing and installation, or after disposal.
The study does not address fly ash used in products like ceiling tiles or carpet backing—other common uses in which the fly ash is not as clearly encapsulated (see”).