At the request of the U. S. Environmental Protection Agency (EPA), the National Academy of Sciences (NAS) convened a world-class panel of experts to review 50 years of research on perchlorate. The panel determined in 2005 that the safe exposure level of perchlorate for all populations, even the most sensitive, is 0.0007 milligrams per kilogram per day, about 24.5 ppb in water.
After nearly two years of review and study, the NAS issued its report on the health implications of perchlorate in January 2005. The NAS committee concluded that a reference dose of perchlorate at 0.0007 milligrams per kilogram per day is appropriate and protective for all populations, including the most sensitive population: fetuses of pregnant women who might have hypothyroidism or iodide deficiency.
In February 2005, EPA established its official reference dose of perchlorate at 0.0007 milligrams per kilogram per day, and translated that number to a Drinking Water Equivalent Level of 24.5 parts per billion (ppb). Subsequently, EPA issued a Health Reference Level of 15 ppb to account for potential exposure to perchlorate from food.
