Perchlorate is the explosive component of solid rocket fuel, fireworks, road flares, and other products. Used heavily by the Department of Defense (DOD) and related industries, perchlorate also occurs naturally and is present in some organic fertilizer. This soluble, persistent compound has been detected in drinking water supplies, especially in California. It also has been found in milk and many foods. Because of this widespread occurrence, concern over the potential health risks of perchlorate exposure has increased, and some states, water utilities, and Members of Congress have urged the Environmental Protection Agency (EPA) to set a federal drinking water standard for this chemical. Regulatory issues involve the relative health benefits and costs of federal regulation, including environmental cleanup and water treatment costs, both of which are driven by federal and state standards. (California and Massachusetts have set standards.) EPA has spent years assessing perchlorate's health effects and occurrence (including its occurrence in food) to determine whether a national standard is warranted. Interagency disagreements over the risks of perchlorate exposure led several federal agencies to ask the National Research Council (NRC) to evaluate perchlorate's health effects and EPA's risk analyses. In 2005, the NRC issued its report, and EPA adopted the NRC's recommended reference dose (i.e., the expected safe dose) for perchlorate exposure. Subsequent studies raised more concerns about potential effects of low-level exposures, particularly for infants in certain cases. On October 3, 2008, EPA made a preliminary determination not to regulate perchlorate; a final decision is expected in late 2008. This report reviews perchlorate contamination issues and related actions.
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