The Facts About Perchlorate

According to the credible data and research available, perchlorate does not cause cancer in humans, does not cause birth defects and is not stored in the body.

  • Since the 1950s, perchlorate has been used in the U.S. and abroad to treat thyroid disorders. As a result, a wealth of information exists about perchlorate and how it relates to human health. The doses used as a medicine are tens of thousands of times greater than the low levels of perchlorate being detected in drinking water today.
  • During the past decade, millions of dollars have been spent studying the possible health risks of perchlorate because of its presence at trace levels in some water supplies. Sound scientific and medical research shows that the low levels of perchlorate being detected in drinking water are not dangerous to human health. These studies on adults, newborns and children provide reason to believe that low levels of perchlorate (even at levels many times higher than the minute amounts being found in some drinking water supplies) also have no measurable effect on pregnant women or fetuses. Additional research is now under way with results expected in the coming months.
  • Credible scientific evidence does not link low levels of perchlorate to thyroid problems or thyroid cancer in humans, according to the National Academy of Sciences' (NAS) report and other credible, peer-reviewed studies by respected and independent medical researchers.
  • Since the early 20th century Chilean nitrate fertilizer containing naturally-occurring perchlorate has been widely used in American agriculture. Current amounts of Chilean nitrate fertilizer products being shipped and used in the United States are substantial. According to the Foreign Trade Division, U.S. Census Bureau, the amounts of sodium nitrate imported from Chile into U.S. ports in 2001 was 88,150 metric tons. California stats
  • In February 2005, the U.S. Environmental Protection Agency 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. This level is consistent with the recommended reference dose included in NAS' January 2005 report on the health implications of perchlorate.
    The NAS report can be viewed at:;=NAP