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.
Researchers at Los Alamos National Laboratory began looking into ways to make less polluting pyrotechnics at the request of the Walt Disney Co., which had been fielding complaints from neighbors about the smoke from nightly displays at Disneyland.
A team of chemists began developing fuel that used less carbon and more nitrogen atoms. As a gas, it created less smoke and allowed for lower amounts of metal coloring agents, also an environmental problem. But the high-tech solution would be too costly for mass use.
Two of the researchers formed a company, DMD Systems, and sell the new pyrotechnics to Disney, as well as many small, indoor venues where smoke and pollution are more of an issue.
