Is Fly Ash Safe?

I consider myself a card-carrying member Environmentalist, once known as the Queen of Green. But I am also a realist, a pragmatist. Yet I flew into a rage when I read on BuildingGreen.com a quote by Russell Perry of Smithgroup, on whether to use fly ash as a replacement for portland cement: "The thought of enabling the coal industry hurts." What???
While in the land of Oz we will be living off of solar energy, and I am strong proponent of taking all measures to move us in this direction, boycotting fly ash is ridiculous. The United States—along with China and India—is expected to account for 88% of the projected net increase in coal consumption between 2006 and 2030. And coal combustion waste (CCW)continues to pile up at rate of about 131 million tons per year in the United States alone. That is reality.

The bad news is that this is waste, when landfilled in its raw form, is toxic and hazardous. However, in 2007, 43% of all CWW produced in the US was devoted to what is termed beneficial uses which binds the heavy metals. For example, fly-ash be used to displace some of the Portland cement powder in the mix ( up to 50% in some cases) for reasons of reduced cracking, binding with the alkali, and creating longer term strength and durability. Innovators have been able to create products depending solely on fly ash in the development of Bricks ( Calstar) and lightweight blocks (Cenocell).

Our photo is of Henry Liu, president of Freight Pipeline Company, holds his company’s Greenest Brick. Unlike conventional clay bricks, these fly ash bricks harden without baking. Testing so far indicates the bricks do not pose a human health threat through leaching or dermal contact.

And toxicity? There are several rigourous tests which have identified the fears of toxicity in fly-ash heavy metals leaching to be unfounded. An excellent article in Environmental Health Perspectives reviews the testing done on gypsumboard, roadfill, poured-in place concrete and fly-ash bricks. NONE identified a hazard to public health.

Yet it seems that Russell at the Smithgroup cannot get past the coal/ fly ash connection. Environmentalists are calling for the material to be deemed hazardous, which would put an end to the beneficial uses and lead to stockpiling. With that comes the potential of another devastating coal ash spill, like that caused when a TVA coal ash pond failed last December and dumped more than a billion gallons of toxic material on to a neighboring community. Will this precipitate a radical change from coal?

A more significant gesture by the Smithgroup or others might be if his entire firm weaned themselves from coal - ie purchase personal, office and jobsite electricity only from non-coal sources, and avoid any product in their specs which uses coal-based electricity in the manufacturing… NOT possible. But any move in that direction would send a louder message, and a more solution generated message than the banishing of fly-ash.