On Burning Hazardous Waste in Cement Kilns

On Burning Hazardous

Waste in Cement Kilns

Dear Editor,

I am writing to comment on your recent article on cement. I really appreciated it, except for the part about hazardous waste. It is NOT burned “relatively safely.” And the high temperatures do not result in “very complete combustion with very low pollution emissions.” This is indeed a very big issue in the environmental field. I will not recommend using cement to any of my clients unless they can be guaranteed it comes from a kiln not burning hazardous waste … the risk is simply not worth it.

The EPA and the cement industry are not giving us all the facts that are available today. And what we DO know is enough to demand more attention and regulation.

Sincerely,

Susan McCrone

Editor’s Response:

Several readers have contacted us to point out that burning hazardous waste in cement kilns may be much more problematic than we had realized. There is concern about toxic emissions from the relatively unregulated kiln smokestacks, toxic residues in cement dust, and even toxicity in the cement itself. One reader sent along an article from The Nation

indicating that cement kilns may be responsible for as much as 10% of annual U.S. lead emissions. Cement dust has generally been disposed of in uncontrolled landfills, or even passed on to farmers to spread on acidic soils in need of neutralization. Toxins can thus be transferred to the soil. Toxins in the cement itself could injure workers who breathe in cement dust during mixing, and it will end up in the concrete or other end-product using the cement. How effectively concrete “locks up” toxins is not known, and the potential for end-user contamination is a concern. This is particularly the case with concrete water mains, through which much of the nation’s potable water is distributed.

The EPA is currently conducting tests of cement kiln emissions, cement dust, and commercial cement in an attempt to measure the extent of the problem. About half the kilns in North America burn hazardous waste as a portion of their fuel. It is likely to take several years before any action is taken to stop the practice among existing users, but new permit applications for burning hazardous waste are reportedly already on hold. Meanwhile concerned users of cement and concrete can request documents verifying that their suppliers do not use cement produced using hazardous waste. Eventually, the move away from such combustion (if it occurs) is likely to lead to price increases in cement, as producers will have to make up for the income they’ve been receiving for taking the hazardous waste from it producers.