A new method for evaluating coal combustion residuals has led the EPA to approve the use of recycled coal ash as an acceptable alternative for Portland cement in concrete. Coal residuals are formed when coal is burned in boilers for power generation or industrial use.

The Environmental Protection Agency (EPA) released an evaluation of the two largest beneficial uses of encapsulated coal combustion residuals (CCR or coal ash); use in concrete as a substitute for Portland cement and the use of flue gas desulfurization gypsum as a substitute for mined gypsum in wallboard.

The evaluation concluded that the beneficial use of encapsulated CCRs in concrete and wallboard is appropriate, because they are comparable to virgin materials or below the agency's health and environmental benchmarks.

"The protective reuse of coal ash advances sustainability by saving valuable resources, reducing costs, and lessening environmental impacts, including reducing greenhouse gas emissions," said Mathy Stanislaus, assistant administrator for EPA's Office of Solid Waste and Emergency Response.

Coal ash is formed when coal is burned in boilers that generate steam for power generation and industrial applications. Slightly more than half of coal ash is disposed of in dry landfills and surface impoundments. The remainder of coal ash is used beneficially, as well as in mining applications.

These two uses account for nearly half of the total amount of coal ash that is beneficially used.