http://www.epa.gov/epawaste/
The United States Environmental Protection Agency Report we enclose via the above link clearly and definitively identifies Coal Ash, in it's several various forms, for what it truly is:
A readily available raw material resource that can serve as an energy-conserving and pollution-preventing substitute for conventional raw materials in the making of Portland-type cement and Portland-type cement concrete, and in a number of other construction and structural applications.
And, right up front, we want to reproduce one conclusion reached by the EPA, "the Agency", as excerpted from deep within the full document:
"(In) the Agency’s May 2000 Regulatory Determination for fossil fuel combustion wastes, EPA’s risk evaluation of the beneficial use of CCPs in cement and concrete concluded that national regulation under the Resource Conservation and Recovery Act (RCRA) is not warranted."