Cold War Contaminant Found In U.S. Drinking Water

"The contaminant, perchlorate, has been used as an oxidizer in rockets, munitions and fireworks since the 1950s... [a] salt with similar characteristics to nitrate, perchlorate wasn't considered very dangerous to humans until a decade ago, when the Environmental Protection Agency warned that it was known to disrupt the functioning of the thyroid gland in people who consumed it. Over the years, defense facilities from Los Angeles to Cape Cod discharged huge amounts of perchlorate onto the ground, contaminating groundwater in many places where it was handled, EPA experts say."