The U.S. Environmental Protection Agency (EPA) is reevaluating its earlier decision not to regulate perchlorate in drinking water, and currently is seeking advice from the National Academy of Sciences (NAS) before making a final determination on whether or not to limit the amount of the rocket fuel ingredient permissible in water supplies.

Meanwhile, the agency has issued an interim health advisory of 15 parts per billion (ppb). EPA expects to issue a final health advisory concurrent with the final regulatory determination for perchlorate. Perchlorate is a naturally occurring and manmade chemical that can affect the functioning of the thyroid gland at sufficiently high doses. It is manufactured and used as an industrial chemical, and can be found in rocket propellant, explosives, fireworks and road flares.

On Oct. 10, 2008, the agency issued a preliminary regulatory determination for public comment in the Federal Register. The notice described the agency’s decision that there is not a "meaningful opportunity for health risk reduction" through a national drinking water regulation for perchlorate. The agency received more than 32,000 comments on the notice.

After considering public comments, as well as recommendations from EPA advisory groups and offices, EPA is asking the NAS to evaluate its derivation of the Health Reference Level of 15 ppb, the use of modeling to evaluate impacts on infants and young children, and the implication of recent bio-monitoring studies.

EPA is replacing the existing preliminary remediation goal of 24.5 ppb with the interim health advisory value of 15 ppb. This goal will be used as a consideration when establishing cleanup levels for perchlorate at Superfund sites.

More information on the perchlorate health advisory, visit