Court Rules EPA Must Regulate Perchlorate

WASHINGTON – A three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit, today unanimously ruled that the U.S. Environmental Protection Agency’s (EPA) decision against regulating the toxic chemical perchlorate in drinking water was illegal. 

The following is a reaction by Erik D. Olson, Senior Strategic Director for Health at NRDC (Natural Resources Defense Council):  

“The court ruled that EPA must regulate perchlorate-contaminated drinking water because the agency had found that it poses a health risk to millions of Americans. After more than a decade of delay and litigation, EPA now must issue a drinking water standard for this widespread and dangerous contaminant. It’s about time.”      

 Judges Sentelle and Tatel issued a joint opinion striking down EPA’s decision not to regulate; Judge Pan issued a separate concurring opinion, rendering a unanimous ruling against the EPA.  

Judges Sentelle and Tatel found that EPA lacked the authority to reverse the agency’s previous decision to regulate this toxic rocket fuel component. Judge Pan agreed that EPA’s action must be struck down, but because EPA was “arbitrary and capricious” in making its decision, not that the agency lacked the authority to do so. She found that EPA’s refusal to regulate based on a finding that decreasing the average IQ of vulnerable children was not an adverse effect “did not meet the statutory standard.” She also noted that EPA decision also “was based on a biased dataset” on perchlorate occurrence in tap water “that was selectively updated.”   

NRDC presented arguments to a three-judge panel of the DC Circuit Court of Appeals in January, 2023, appealing a Trump-era 2020 decision to not regulate perchlorate. The chemical is a toxic component of rocket fuel associated with brain damage in fetuses and infants, leaving millions of people unknowingly exposed to the chemical through their tap water.   

Perchlorate, widely used in rocket fuel and munitions, and also a component of fireworks and certain other industrial chemicals, was the first unregulated drinking water contaminant for which EPA proposed a standard in nearly a quarter century under the provisions of the Safe Drinking Water Act Amendments of 1996. The Defense Department (DOD) and its contractors are major users of perchlorate and there are innumerable DOD facilities where perchlorate pollution has been found. DOD has opposed strict controls on perchlorate, in an apparent attempt to minimize its cleanup costs.  
Since perchlorate is unregulated, there is no federally required monitoring of tap water or requirement to inform a community of contamination. In 2011, the EPA formally decided that perchlorate should be regulated because it is toxic and widespread, with the drinking water of as many as 16 million people contaminated by the chemical. When the Agency failed to develop a standard by the deadline, NRDC sued, and then secured a court-approved consent decree requiring the EPA to issue a drinking water standard for perchlorate by 2019.    
NRDC agreed to extend the court-ordered deadline to 2020 when the Trump Administration asked for additional time. Ignoring the court order, the Trump EPA announced in 2020 that it was purporting to rescind the Obama-era finding that a standard should be set. The Trump Administration contended that EPA’s 2008 health advisory for perchlorate in drinking water is far more protective of health than needed. 

NRDC (Natural Resources Defense Council) is an international nonprofit environmental organization with more than 3 million members and online activists. Established in 1970, NRDC uses science, policy, law, and people power to confront the climate crisis, protect public health, and safeguard nature. NRDC has offices in New York City, Washington, D.C., Los Angeles, San Francisco, Chicago, Bozeman, MT, Beijing and Delhi (an office of NRDC India Pvt. Ltd). Visit us at and follow us on Twitter @NRDC.  



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