The announcement is the latest development in a more than decade-long regulatory dispute over perchlorate, which disrupts thyroid function and has been linked to lower IQ scores and behavioral problems in young children. Environmental groups said the agency’s posture puts millions of people at risk, particularly infants and fetuses most vulnerable to the chemical’s effects.
The Environmental Protection Agency said Monday it will propose a drinking water limit for perchlorate, a chemical used in rockets, fireworks, and other explosives — but only because a federal appeals court ordered it to act.
The agency said it would seek public comment on proposed limits of 20, 40, and 80 parts per billion, and require roughly 66,000 water utilities nationwide to test for the chemical. But it also said the regulation would not significantly benefit public health and that the costs imposed on utilities would largely not be justified by the benefits.
“Due to infrequent perchlorate levels of health concern, the vast majority of the approximately 66,000 water systems that would be subject to the rule will incur substantial administrative and monitoring costs with limited or no corresponding public health benefits as a whole,” the agency wrote in its proposal.
The health hazard
Perchlorate occurs naturally in some regions and has seeped into groundwater at defense, aerospace, and manufacturing sites, with contamination concentrated in the Southwest and along sections of the East Coast. The chemical is a concern because it disrupts thyroid function, which can be particularly damaging for fetuses and young children — the EPA has previously linked perchlorate exposure to lower IQ scores and increased rates of behavioral problems.
The EPA said its current data shows perchlorate is not widespread in drinking water. “We anticipate that fewer than one‑tenth of 1% of regulated water systems are likely to find perchlorate above the proposed limits,” the agency said. It added that utilities whose initial testing showed no concern could test less frequently afterward, and that it would work with states and communities to reduce contamination at the source.
More than a decade of regulatory delay
The EPA determined in 2011 that perchlorate posed a sufficient threat to public health to require regulation, based on estimates that it could be in the drinking water of roughly 16 million people. Under the Safe Drinking Water Act, that determination required the agency to propose and finalize regulations by set deadlines — requirements the agency did not meet.
The Natural Resources Defense Council sued in 2016 to force the EPA to act. During the first Trump administration, the EPA proposed a standard that the NRDC said was less restrictive than any state limit. The agency never implemented it, then reversed course entirely in 2020, saying a new analysis had found perchlorate to be less dangerous and less common in drinking water than previously thought.
A federal appeals court overruled that reversal, finding that perchlorate remains a significant and widespread public health threat and ordering the agency to propose a regulation. Monday’s announcement is the agency’s response to that order.
Environmental groups remain skeptical
“Members of the public deserve to know whether there’s rocket fuel in their tap water. We’re pleased to see that, however reluctantly, EPA is moving one step closer to providing the public with that information,” said Sarah Fort, a senior attorney with the Natural Resources Defense Council.
The NRDC added that even a 20 parts per billion limit would be weak and put at risk the health of “millions of people across the country, especially fetuses and young infants who are particularly vulnerable to this toxic chemical.”
Drinking water against the EPA’s broader direction
EPA Administrator Lee Zeldin has sought widespread rollbacks of environmental rules and promoted oil and gas development. The agency’s actions on drinking water, however, have been more measured. The EPA said it would retain the Biden administration’s strict limits on two of the most common types of PFAS — so-called forever chemicals — in drinking water while giving utilities more time to comply, but would eliminate limits on other PFAS types.