30 years ago the concrete industry was resisting the move to use coal fly ash as a cement replacement or as an additive in concrete. Now the industry is fighting to keep it as an important part of concrete.
In the United States, there are almost 900 Coal Ash landfills and surface impoundments nationwide. In December 2008 the collapse of the Tennessee Valley Authority's Kingston Fossil Plant wet storage embankment allowed 5.4 million cubic yards of coal fly ash to be released into the Emory River. A few weeks later, a smaller TVA-plant in Alabama also had a spill contaminating Widows Creek and the Tennessee River. Shortly after these accidents the EPA and other organizations began to process of trying to have coal fly ash reclassified as a type C material under RCRA material standards. It was classified as a Class “D” material, which left the regulation of it up to each state. This change would allow the EPA to regulate every aspect of fly ash.
On May 4 2009, the EPA issued its initial ruling. It has opened a 90 day public hearing period. The EPA has proposed 2 options for regulating the disposal and impound of fly ash. The first would classify it as type “C” martial under the RCRA standards, which creates a comprehensive program of federally enforceable requirements. The second option will classify it under “D”, which will allow the EPA to set performance standards for waste management facilities. In both cases, the EPA will keep in place the Bevill exemption for beneficial uses of coal ash in which they are recycled as components of products instead of placed in impoundments or landfills.
I have included some links here for additional information:
Technical information about Fly Ash in Concrete
Wikipedia – Fly Ash
Intermountain Construction Article