02 January 2010

Fly Ash?

Fly ash is frequently touted as "sustainable" and "green." It is used by manufacturers of cement and concrete products, and claim LEED credit for recycled content.

Fly ash is a by-product of the burning of coal. Once it was released into the atmosphere following combustion, it is today scrubbed from the exhaust. The srubbed fly ash is used in the manufacture of concrete and cement products, usually as a substitute for Portland cement.

Problem one: We need to stop the burning of coal altogether. The green movement and now green industry should not support the coal industry in any way, shape or form. Granted, while we wean ourselves of our dependency we will continue to make mountains of the stuff, and its use in cement redirects the material from its other potential destination, which is the landfill. However, we cannot continue to allow it to be considered green.

Problem two: Fly ash contains significant toxic impurities, including arsenic, barium, beryllium, cadmium, chromium, cobalt, lead, strontium, thallium, vanadium. The potential health effects are currently unknown. Strontium levels are particularly high.

I understand the arguments as to why its use is a good thing. I'd rather see it in cement and concrete products than in a landfill. But to consider it green and credit it as a LEED point, giving boasting rights to the coal industry, is pure illusion.

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