There's plenty of irony in the possibility that fly ash, a by-product of coal combustion, now may be classified as a hazardous waste by the U.S. Environmental Protection Agency. It has been successfully recycled for years in what previously had been considered an environmental triumph. Punishing the sound environmental use of fly ash, especially as a substitute for cement in concrete, is the wrong direction. Exempting fly ash from Resource Conservation and Recovery Act provisions has allowed coal-combustion products (CCPs) to develop into a growing business. The use of fly ash in concrete is considered environmentally responsible because it replaces up to 25% of the high-carbon-footprint cemeiit content in concrete, depending on the specific mix for a project (ENR 4/12 p. 12). In both 1993 and 2000, EPA determined that CCPs did not warrant management as a hazardous waste.
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