Perchlorate Contamination of Drinking Water: Regulatory Issues and Legislative Actions

Mary Tiemann
Specialist in Environmental Policy


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 have involved the health risk reduction benefits and the costs of federal regulation, including environmental cleanup and water treatment costs, both of which are driven by federal and state standards. 

EPA has spent years assessing perchlorate's health effects and occurrence to determine whether a national standard is warranted. The Food and Drug Administration (FDA) has supported this effort by testing produce and other foods for the presence of perchlorate. 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 the potential effects of low-level exposures, particularly for infants in certain cases. 

In October 2008, EPA made a preliminary determination not to regulate perchlorate in drinking water. Then, in early January 2009, the agency announced that it again would seek advice from the NRC before making a final determination. EPA also announced that it was replacing the preliminary remediation goal for perchlorate of 24.5 parts per billion (ppb) with an interim health advisory, which contains a value of 15 ppb. 

In August 2009, the EPA Administrator announced that the agency would reevaluate the science regarding perchlorate's potential health effects, with particular emphasis on evaluating the effects of perchlorate exposure on infants and young children. The agency determined not to ask the NRC to conduct further review of issues related to perchlorate, having concluded that additional NRC review would unnecessarily delay the regulatory decision-making process. EPA intends to consider public comments before making a final regulatory determination. Legislation (H.R. 3206) has been introduced to require EPA to promulgate a drinking water standard for perchlorate. This report reviews perchlorate contamination issues and related developments.


Date of Report: January 11, 2010
Number of Pages: 10
Order Number: RS21961
Price: $29.95

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