RE: OEHHA Fails to Provide Legitimate Scientific Rationale for a New Perchlorate Public Health Goal

California’s Office of Environmental Health Hazard Assessment (OEHHA) has failed to provide scientific evidence that the state’s perchlorate public health goal (PHG) needs to be reduced, and continues to rely on questionable research that is inconsistent with 60 years of scientific investigation, according to comments filed this week by Intertox on behalf of the Perchlorate Study Group (PSG).

Intertox’s comments on OEHHA’s revised draft perchlorate PHG conclude there is no legitimate scientific or public health basis to justify OEHHA’s proposed change in the PHG from 6 parts per billion (ppb) to 1 ppb. Moreover, the comments highlight how substantial scientific concerns with OEHHA’s 2011 draft PHG document were not addressed in the new proposal and emphasize that the scientific approaches OEHHA employed cannot produce a scientifically reliable PHG.

Among Intertox’s many comments:

  • OEHHA has failed to provide any evidence that the current PHG is not protective, nor has it defined any public health benefits that would come from lowering the goal.
  • The draft document misrepresents the weight-of-evidence for perchlorate health effects in order to support its conclusions. OEHHA uses five studies as the foundation of its assessment, four of which are presented with calculations by OEHHA, not the actual study authors. In contrast, several peer-reviewed studies that do not support OEHHA’s conclusions are noticeably excluded by OEHHA. This is particularly troubling, given that the best-available science is contrary to OEHHA’s assertions and suggests its studies are severely limited
  • More than 60 years of scientific study makes it clear that exposure to perchlorate at environmental levels has no effect, let alone an adverse effect, on the human body. OEHHA’s current PHG of 6 ppb is already more than 40 times lower than the recognized no-effect level.
  • OEHHA relies on untested and unsupportable assumptions and methodologies to support its position. As one example, the agency assumes a 95th percentile one-month-old infant would consume 280% of their blood volume in drinking water every day. This is the equivalent of the average adult consuming nearly four gallons of tap water daily.

PSG has strongly advised OEHHA that its proposal and supporting documents will likely be unable to withstand scientific scrutiny and may be indefensible in the face of the preponderance of scientific evidence.

Additional background:

  • 1 ppb is roughly equal to a half teaspoon of material diluted in an Olympic-sized pool
  • Adverse effects of perchlorate exposure have not been demonstrated in humans, even at levels as high as 14,000 ppb, assuming an average adult drinking 2 liters of tap water daily.
  • Claims that perchlorate has been linked to thyroid problems, birth defects or other serious health problems are inaccurate – no published research exists in more than 60 years of scientific study to support these claims. More…
  • According to OEHHA’s Guide to Public Health Goals for Chemicals in Drinking Water, a PHG “is not a boundary line between a ‘safe’ and ‘dangerous’ level of a contaminant, and drinking water can still be considered acceptable for public consumption even if it contains contaminants at levels exceeding the PHG.”

Please visit for factual information on perchlorate, or contact Bill Romanelli at 916-448-3152 or 916-212-1446 (cell).