Replacing perchlorate in fireworks makes them safer for environment

By Meredith Cohn | meredith.cohn@baltsun.com

July 4, 2009

As millions of Americans head out for their annual Fourth of July fireworks, they might not realize the chemical that makes the shows so bright also poses an environmental threat. But researchers are developing new, greener pyrotechnics that already are being used at Disneyland and some indoor concerts.

The new fireworks use alternatives to perchlorate, a salt that provides oxygen to the combustible elements in fireworks so they can burn.
The chemical is considered particularly harmful to pregnant women and small children because of its ability to block absorption of iodine in the thyroid, a gland that controls metabolism and growth. The threat isn’t considered sufficient for the government to ban the mostly Chinese-made pyrotechnics that use it, but the Environmental Protection Agency is studying the impact and plans to develop regulatory standards.

"It’s definitely a problem," said John Conkling, an adjunct professor of chemistry at Washington College in Chestertown and an industry consultant. "How big a problem, no one can say. We need some more good science."
In the past five years, researchers have discovered that perchlorate can concentrate not only in the ground and water where fireworks are made, but also where they are launched. Duds can pose a particular problem, Conkling said, because properly working fireworks burn much of their perchlorate.
One recent study published in the American Chemical Society’s journal Environmental Science & Technology found after fireworks displays from 2004 to 2006 on a lake in Oklahoma that perchlorate was found in the lake, fish and groundwater. It only dissipated in surface water, and only after several weeks.

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