EPA has found that a dangerous chemical prevalent in drinking water poses more risks than previously determined, including outsize cancer threats.
The agency announced Friday that it has broadened its scope for 1,4-dioxane, a likely carcinogen that can crop up in shampoos and cleaning products, to include air and water exposures on the general population — an addition to the risk evaluation completed under the Trump administration that centered on work-related exposures.
According to a draft supplement, 1,4-dioxane is estimated to pose a cancer risk “higher than 1 in 1 million for a range of general population exposure scenarios, including to fenceline communities, associated with drinking water sourced downstream of release sites and for air within 1 km of releasing facilities.”
The findings offer a grim assessment of the chemical’s threat to the public beyond what regulators had previously concluded.
The 1,4-dioxane draft assessment has been one of the most anticipated chemical reviews from the Biden administration after regulators decided to reopen a number of finalized decisions made under former President Donald Trump.
During the prior administration, EPA faced an onslaught of criticism over close ties to industry and moves to downplay the risks associated with a range of toxic substances.
Advocates aimed particular ire at the agency’s moves under the overhauled Toxic Substances Control Act, including reviews for the first 10 chemicals deemed to be of the greatest regulatory importance due to public health concerns.
The 1,4-dioxane assessment proved especially thorny, with EPA determining that the solvent, despite its carcinogenic threat, ultimately posed no threat to the public or the environment.
That conclusion drew heated legal fire, with environmental groups suing over the determination and a coalition of 14 states and two cities later launching their own litigation. New York Attorney General Letitia James (D) has been particularly emphatic on the issue, due to the state’s ongoing struggles with 1,4-dioxane contamination.
The chemical often appears as a byproduct during manufacturing processes, which can lead to its presence in items like soap.
While the Trump administration acknowledged health risks for workers, regulators stopped short of evaluating the threat to the general public through drinking water and air. That sparked considerable concern from some Scientific Advisory Committee on Chemicals members, who highlighted the chemical’s risks, including both cancer and adverse effects to the liver and nasal tissue.
“This is particularly concerning for drinking water,” SACC members noted.
Along with other assessments, the Biden administration quickly moved to address such concerns, with EPA’s top chemicals official, Michal Freedhoff, announcing in June 2021 that the 1,4-dioxane determination would be reopened and updated. “We believe we will need to supplement [that chemical],” Freedhoff said at the time.
Not yet available is EPA’s unreasonable risk determination for the chemical, which the agency said “will also be released in the coming weeks for public comment.”
The new findings account for much of the scrutiny that critics argue was absent from the initial evaluation, including implications for fence-line communities. EPA noted that the draft “addresses previous feedback from the TSCA SACC and public comments” through measures including the “use of multiple years of data on releases to air and water and consideration of releases to groundwater.”
As part of the draft process, however, the agency acknowledged that some of the occupational monitoring data for 1,4-dioxane is “several decades old.” EPA said it welcomed input offering updates and a more contemporary look at occupational monitoring data.
While 1,4-dioxane has not drawn as much national attention as contaminants like PFAS, known as “forever chemicals,” the compound is among notorious water pollutants that have drawn concern from regulators.
The Biden administration’s highest-profile crackdown has hit PFAS — or per- and polyfluoroalkyl substances — the hardest, including landmark measures under the Safe Drinking Water Act to rein in some of those chemicals.
But advocates and public health experts have expressed optimism that 1,4-dioxane could be among the next contaminants singled out under the Safe Drinking Water Act, along with other statutes.
Meanwhile, the chemical continues to spark fears in areas like Ann Arbor, Mich., which has dealt with a toxic plume of 1,4-dioxane in groundwater. In a preliminary assessment offered last month, EPA said there was a strong chance that the site could be eligible for Superfund status due to toxicity concerns.
Other parts of the country have similarly grappled with 1,4-dioxane pollution, largely in water.
