Greer Study: Good Science Validated by Experts

Tuesday, June 14, 2005

Recently, questions have been raised in press reports concerning the Greer study – a peer-reviewed, scientific study upon which authoritative experts have relied when examining the health effects of perchlorate. It is important for the media and public to be mindful of the following points:

  • The Greer study has been thoroughly peer-reviewed, published and judged to be a high quality and valid study by one of the most respected scientific bodies in the nation – the National Academy of Sciences (NAS). It also has been validated by the U.S. Environmental Protection Agency (EPA), the State of California and other independent, credible researchers. This review and validation process has given the public access to the best available science regarding safe levels of perchlorate exposure.
  • The NAS committee relied on much more than the Greer study in making its recommendation. To quote from its report, NAS “considered published and unpublished epidemiologic data in forming its conclusions regarding the possible effects on thyroid function of exposure to perchlorate and in assessing the relevant exposure limits. The committee emphasized studies with the soundest scientific methods and studies that included biologically sensitive groups, such as pregnant women, fetuses, and neonates.”
  • Also, according to the NAS report, “The committee recognizes that its recommendations would lead to an RfD of 0.0007 mg/kg per day. That value is supported by other clinical studies, occupational and environmental epidemiologic studies, and studies of long-term perchlorate administration to patients with hyperthyroidism.”
  • In a June 3, 2005 article in the Riverside Press-Enterprise, Dr. Richard Johnston, chairman of the NAS perchlorate panel and associate dean of research and development at the University of Colorado Medical School, stated as follows: “The Greer findings were consistent with several other studies on humans, and that body of work gave the committee confidence in Greer’s conclusions about the amount of perchlorate a healthy person can consume.”
  • In that same article, Bill Farland, acting deputy assistant administrator for science at the EPA’s Office of Research and Development, said the National Academy’s work was thorough, and that EPA concluded it was a solid base for the policy adopted in February.
  • In a June 15, 2005 article in the Gilroy Dispatch, Dr. Richard Corley, a staff scientist at the Pacific Northwest National Laboratory in Washington state and a member of the NAS committee, defended the NAS report and indicated the NAS relied on several studies in making its conclusions. Dr. Corley is quoted in the Dispatch as follows: "'The results from Greer were not taken in isolation. They were consistent with other studies on humans, with ongoing studies. We were very careful."