Let's Clear Up the Fly Ash Dilemma: Is it Danger or is it Not?

(Engineering News Record 4-14-2010) 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 cement content in concrete, depending on the specific mix for a project. In both 1993 and 2000, EPA determined that CCPs did not warrant management as a hazardous waste.The use of ash and other waste products in concrete is far different from uses in impoundments and embankments, where the leachate can contaminate groundwater with chemicals that include cadmium and arsenic.
 
Potential problems with coal fly ash coming into contact with water have been recognized for a long time. More than 18 years ago, researchers at the University of Florida concluded that its use as an embankment had the fewest dangers, but “this option is still considered to be in the experimental stage.” They called for more research.
 
Refining Uses
Fly-ash producers and contractors have been refining the uses of different types of ash. For example, bottom ash has been used as a structural fill for some time, but the use of fly ash as an aggregate for masonry just started in the last year or two because of higher environmental awareness of the sustainability issue. Experts do caution, however, that bottom-ash material should not be used in concrete-block products.Personal injury lawsuits are an American right, and the courts are the last refuge for injured or sick people, especially given the health-care system’s problems. But no one yet knows who has been injured by fly ash, either in its use or handling. Contamination did pollute land in Tennessee, where an earthen retaining wall collapsed, reinforcing that it should be used away from water.
 
Until a quick and convenient way is found to wean our country from coal, we must live with it and the by-products of burning it. EPA can add to our knowledge with more research and guidance about safe practices. Further, it can go a long way toward preventing a snowballing series of problems by avoiding an overly encompassing ruling. As the American Coal Ash Association said, “Addressing the disposal problem in the wrong way can destroy one of the greatest recycling stories in recent American history.”
 
To view the original article please go to: http://enr.construction.com/opinions/editorials/2010/0414-FlyAshDilemma.asp

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Correction submitted

The ACAA has written to ENR correcting the misstatements regarding the use of coal combustion products in masonry units. We have been told this letter will be published in an upcoming issue of ENR.