Science Experts Tell EPA to Regulate Toxic Perchlorate

One of the many travesties in the failure to properly protect drinking water in the United States is EPA’s decades-long inability to set an enforceable drinking standard for perchlorate, a chemical that harms the thyroid – critical for normal growth and development – and that contaminates drinking water systems serving over 17 million people in the U.S.  EPA determined back in 2011 that perchlorate meets the criteria for regulation as a contaminant under the Safe Drinking Water Act. EPA concluded that, “perchlorate may have an adverse effect on the health of persons and is known to occur in public drinking water systems with a frequency and at levels that present a public health concern.” (EPA 2011).

This isn’t just a Trump/Pruitt problem. NRDC has been pressing EPA for years, through Republican and Democratic administrations to act. Unfortunately, EPA has long been under strong pressure from industry and the Pentagon and its contractors to avoid setting a strong drinking water standard for perchlorate (DOD is a major source of perchlorate pollution due to its use in rocket fuel and munitions at its facilities across the country). We sued the Agency in 2016 to set a health-protective drinking water limit for this toxic chemical (NRDC Feb 2016).

Now, the final peer review report from an expert panel has concluded that EPA should proceed to set a health-protective drinking water standard for perchlorate, even while expressing some concerns that EPA’s approach may still be underestimating the health risks posed by drinking perchlorate (see Final Peer Review report March 2018). NRDC shares the concerns of some expert peer reviewers that EPA’s approach may underestimate risk, particularly where exposures take place during early life development of critical systems, that could lead to neurobehavioral impairments.  In setting a drinking water standard, EPA should use uncertainty factors (UFs) to address these limitations, and to ensure that vulnerable populations will be protected.

Perchlorate is a hazardous chemical component of explosives that is used in rocket fuel, munitions, fireworks, air bags and in food packaging. It also occurs naturally in Chilean soil nitrate, which has historically been used as fertilizer here in the US (EPA 2014). According to a 2010 GAO report, “Perchlorate has been found in water and other media at varying levels in 45 states, as well as in the food supply, and comes from a variety of sources.” EPA reported that approximately 160 public water supplies tested – serving over 17 million people- had perchlorate at 4 ppb (the lowest level that was looked for) or higher (73 Federal Register 60262, 60270 October 10, 2008).

FDA measured perchlorate in over half of food samples it analyzed, including baby foods and infant formula. Perchlorate is also in human breast milk (see Kirk et al 2007 and Pearce et al 2007). Learn  more from blogs by Tom Neltner of Environmental Defense Fund (EDF) here.

For an acute contaminant like perchlorate where even short-term exposures can have health consequences for vulnerable populations, consumers need reliable information about the health concerns associated with perchlorate, what routes of exposure are of greatest concern, and how to respond to violations in the drinking water standard when they may occur.

Effective action by EPA to regulate perchlorate would not only protect our health but would reverse bad public policy that has put us at risk for years. After decades of accumulated science on perchlorate’s health harms, and with years of opportunity for public and industry input and comment, it is past time for EPA to protect people’s health by preventing harmful exposure to perchlorate in drinking water.

About the Authors

Jennifer Sass

Senior Scientist, Health program

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