Answer to Question #3121 Submitted to "Ask the Experts"

Anything extracted from the earth's crust usually contains trace amounts of naturally occurring radioactive material—namely uranium, thorium, radium, their radioactive decay products, and potassium. The amount of radioactive material in fly ash may vary by a factor of more than 10, depending on the source of the coal. Generally coal mined in the western states is lower in radioactivity than eastern state coal. The radioactivity tends to stay with the fly ash and because of weight lost during burning, on a weight basis, the amount of radioactivity increases in fly ash. Since brick, concrete blocks, and concrete are made from material extracted from the earth, they also contain naturally occurring radioactive material. The concentrations are generally comparable to that of coal.

The scientific community has not reached a definitive conclusion regarding the health effects of very low radiation exposure. Some feel there is an effect, others feel there is not an effect. Generally one can state that the health effects of living in a house made of fly ash block would be similar to that resulting from living in a house made of brick or concrete block.

I don't think that you can find fly ash or much of anything else that is absolutely free of radioactive materials. Even wood contains trace amounts of radioactive carbon.

This response is limited to radioactivity considerations and does not address chemical hazards which may or may not be present.

L. Max Scott, CHP