In 1985, perchlorate contamination was discovered at Superfund sites in California; however, the extent of perchlorate contamination of water sources nationwide was not revealed until 1997. Today, over 11 million people have perchlorate in their public drinking-water supplies at concentrations of 4 ppb (4 :g/L) or higher. Because of the controversy surrounding the concentration at which perchlorate should be regulated, the Department of Defense (DOD), the Department of Energy (DOE), the National Aeronautics and Space Administration (NASA), and the Environmental Protection Agency (EPA) asked the National Research Council to assess the potential adverse health effects of perchlorate ingestion from clinical, toxicologic, medical, and public-health perspectives
