A federal appeals court ruled Tuesday that the Environmental Protection Agency must regulate perchlorate, reversing a rollback on a drinking water contaminant linked to brain damage in infants.
A three-judge panel of the U.S. Court of Appeals for the District of Columbia ruled unanimously in an appeal brought by the Natural Resources Defense Council last year after the EPA, under the Biden administration, stood by the rollback. Two judges wrote that the EPA had no authority to withdraw from a 2011 determination that perchlorate should be regulated.
Circuit Judge Florence Pan, in a concurring opinion, went further. She called the EPA’s decision not to regulate perchlorate “arbitrary” and “capricious” and rejected the agency’s assertion that perchlorate was occurring at lower levels than previously thought. That assertion relied on a ”biased dataset that was selectively updated,” wrote Pan, who was appointed by Biden.
The EPA announced in 2020 it wouldn’t regulate perchlorate. The agency said the decision was based on the “best available peer-reviewed science.”
That prompted the NRDC’s appeal. Erik D. Olson, NRDC’s senior strategic director for health, called Tuesday’s ruling “about time.”
“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,” Olson said. “After more than a decade of delay and litigation, EPA now must issue a drinking water standard for this widespread and dangerous contaminant.”
An EPA spokesman said the agency was reviewing the decision. The American Chemistry Council, an intervenor on behalf of the EPA, declined immediate comment. Western Growers, another intervenor, did not immediately respond to a request for comment.
Perchlorate has been used in the U.S. for decades, particularly by the military and defense industries. It’s commonly found in munitions, fireworks, matches and signal flares. Perchlorate from runoff contaminates the drinking water of as many as 16 million Americans, the Obama administration said in 2011 when it announced EPA would for the first time set maximum limits.
Exposure to the compound can damage the development of fetuses and children and cause measurable drops in IQ in newborns, the American Academy of Pediatrics said in 2019, when it called for stringent federal limits. Perchlorate damages human development by disrupting thyroid gland functioning.
In its 2020 review, the EPA said state-level regulations and cleanup activities at contaminated sites had lowered the health risks posed by the compound. But the NRDC argued that not all states had set safe limits, and perchlorate was one of the most problematic chemicals in drinking water.
The Associated Press contributed to this article.