US EPA should withdraw its 2011 regulatory determination to set a national water standard for perchlorate and revise its perchlorate reference dose and health advisory, in accordance with the findings in its Proposed Perchlorate Rule published on June 26, 2019. The best available science, public health information, statutory direction from Congress, Federal law and long-standing agency practice oblige EPA to do no less.

EPA’s analysis shows repeatedly that additional regulation of perchlorate at the national level offers no meaningful opportunity to improve public health and that the costs outweigh the benefits – by as much as 3000-fold. Under the requirements of the Safe Drinking Water Act (SDWA), as well as the direction of Congress that EPA should prioritize its decisions based on the greatest threats to public health, EPA is compelled to withdraw its 2011 determination rather than moving forward with setting a national drinking water standard.

There are multiple, consistent lines of evidence that further support EPA’s withdrawal:

  1. EPA’s modeling demonstrates that levels of perchlorate found in drinking water have no health effects on either the typical U.S. consumer or the most sensitive subpopulations.
  2. A comparison of perchlorate and other SDWA contaminants shows that a decision to withdraw the perchlorate determination is consistent with past decisions not to regulate.
  3. Independent public health agencies like the U.S. Food and Drug Administration (FDA) have already concluded that doses greater than those found in drinking water do not warrant regulation.
  4. The findings of the National Research Council of the National Academies of Science (NAS), make clear that levels of perchlorate found in the environment do not pose a risk to public health.
  5. EPA’s traditional method of evaluating SDWA contaminants—calculation of a Health Reference Level (HRL)—demonstrates there is very little exposure to perchlorate above the HRL and thus very little potential risk.

Additional background:

  • More than 60 years of scientific study show that exposure to perchlorate at levels found in drinking water has no adverse health effect on the human body.
  • 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…
  • The scientific database on perchlorate dates back to its use as a medicine, involving doses thousands of times higher than amounts in the environment today.
  • The National Academy of Sciences (NAS) determined in 2005 that levels of perchlorate in drinking water below 24.5 ppb have no measurable effect on human health. In the areas where perchlorate has been detected, recent data show that essentially all concentrations are less than 10 ppb. It is unlikely anyone in the U.S. is being exposed to perchlorate levels above the NAS’ No Observed Effect Level, and current studies show that the amounts of perchlorate in the environment are declining.
  • The Safe Drinking Water Act requires three key criteria be met before a compound can be regulated: (1) it may have an adverse effect on human health, (2) it occurs in public drinking water systems at a frequency and at levels of public health concern, and (3) federal regulation of the substance presents a meaningful opportunity for health risk reduction. Perchlorate meets none of these criteria.

Please visit for factual information on perchlorate, or contact Bill Romanelli at 916-212-1446.