According to Scientific American "coal ash is more radioactive than nuclear waste." After various studies it has been determined that:
the waste produced by coal plants is actually more radioactive than that generated by their nuclear counterparts. In fact, the fly ash emitted by a power plant --a by-product from burning coal for electricity-- carries into the surrounding environment 100 times more radiation than a nuclear power plant producing the same amount of energy.
Perhaps you remember to billion plus gallon ash sludge spill in Harriman, TN. The ash is full of heavy metals including arsenic, cadmium, mercury, thallium, which persist in the environment for a very long time.
Perhaps folks remember Times Beach, Missouri which had to be destroyed because of dioxin mixed with oil that was placed on the roads. So how is using fly ash for sandblasting significantly different? There are no toxic controls that I know of with sand blasting operations?
How does using fly ash, and other coal remnants, as landfill keep it out of the water system?
Certainly, mixing it gypsum in sheet rock/wallboard seems dumber still.
How many folks, myself included, do their own home repairs? As you are mixing you concrete, or replacing a damaged wall in your home, do you seal the area, wear a mask, dispose of the residue in an approved toxic site? I don't, and frankly it never occurred to me that I was potentially placing myself - or others - at risk. There is no warning sign that I have ever seen that says that concrete or sheet rock contains toxic material or heavy metals.
I've also been around significant demolition of sites in my life. Imagine the dust that settles over everything and ends up in the landfill, or washed down the street drains. There are no precautions taken there for the escape of this type of toxic materials either.
However, the idea of reusing / repurposing toxic materials could certainly be extended. How about all those spent rods from nuclear power plants and radioactive material from medical facilities. Why not grind it up and use it in the same construction materials? Oh, I forgot. The United States does use "depleted" uranium in its heavy munitions, and as counterweights in airplanes. Never mind. That is nuts too if you ask me.
And they say there is "clean" coal.
Action form: Tell the EPA to strictly regulate the disposal of contaminated coal waste
Action form: Tell TVA to Take Responsibility for Toxic Coal Spills!