In response to a recent study by the U.S. Food and Drug Administration that found widespread perchlorate contamination of food and beverages, environmental health advocates are calling on the federal government to set a strict tap-water safety standard for the toxic chemical, which is used in the manufacturing and firing of rockets and missiles.

The problem of environmental perchlorate contamination is particularly pressing for young children, who eat and drink relatively more food and water for their size compared to adults. According to an analysis by the Environmental Working Group, levels of perchlorate in tap water even as low as 4 parts per billion (ppb) will cause the average two-year-old to exceed the Environmental Protection Agency's safe exposure level. That's why EWG is calling for tight limits on the contaminant, which can be controlled through filtration and cleanup of spills.

"Every final or proposed water standard for perchlorate fails to provide adequate protection for children," Dr. Anila Jacob, an EWG senior scientist, said in a statement. "The EPA has issued a clean up standard of 24 ppb, nowhere near a level protective of children."

Besides being at risk for higher exposures, children are especially sensitive to perchlorate's effects. The chemical can block the thyroid gland's access to iodine and decrease production of hormones necessary for maintaining normal growth and brain development in children.

A May 2005 study [PDF] by the U.S. Government Accountability Office found widespread perchlorate contamination across the United States, including the South. According to the GAO, there are seven facilities and sites affected by perchlorate contamination in Alabama, four in Arkansas, six in Florida, three in Georgia, two in Louisiana, one in Mississippi, seven in North Carolina, four in South Carolina, two in Tennessee, four in Virginia, one in West Virginia -- and a whopping 118 in Texas, where GAO found more contaminated sites than any other state.

While many of the perchlorate-contaminated sites are on or near military installations, they also include municipal water systems in densely populated areas. For example, drinking water from the the city of Levelland in Hockley County, Texas is contaminated with perchlorate at levels of 123 ppb, while drinking water from the Atlantic Beach municipal system in Duval County, Fla. contains 200 ppb.