Revised EPA Risk Evaluation Accounts for Workplace Exposures to Solvent 1,4-Dioxane

EPA has released a supplement to its risk determination for 1,4-dioxane, a solvent used in laboratory and industrial applications, as well as in dish soaps and laundry detergents used by cleaning services and laundromats. This supplement considers the potential effects of 1,4-dioxane exposures on workers and members of the general population, including when the solvent is a byproduct of manufacturing processes, according to a Nov. 13 press release. Exposure to 1,4-dioxane may result in cancer and damage to the liver and nasal tissue. EPA had already determined that 1,4-dioxane presents an “unreasonable risk of injury to human health” in a risk determination finalized in December 2020. However, members of the Scientific Advisory Committee found that this risk evaluation for 1,4-dioxane did not evaluate all the ways people could be exposed to the solvent. “The final supplement to the 1,4-dioxane risk evaluation addresses these concerns and provides the public with a more complete understanding of the risks presented by 1,4-dioxane,” EPA states.

In addition to 1,4-dioxane’s applications as a solvent, it is also used in the manufacture or processing of other chemicals, such as adhesives and sealants, or may be generated as a byproduct. The chemical may be present as a contaminant in consumer and commercial dish soaps and laundry detergents. Workers who handle 1,4-dioxane in industrial and manufacturing applications and in commercial applications may be at risk through inhalation and dermal exposure, EPA found. Of the 26 industrial and commercial conditions of use of 1,4-dioxane evaluated by EPA, 22 “significantly contribute to the unreasonable risk to workers.” These include the chemical’s uses in functional fluids, such as metalworking fluid, as well as in film cement, spray polyurethane foam, printing, hydraulic fracturing, and textile dyes. The complete list of industrial and commercial uses found to contribute to risks to workers is available in EPA’s press release.

The supplement to the 1,4-dioxane risk evaluation also addresses risks to fenceline communities and the general population from inhaling the chemical or ingesting it in contaminated water. When cleaning products containing 1,4-dioxane are washed down the drain or disposed of in landfills, the substance may enter surface and drinking water.

EPA next plans to take risk management steps. “EPA will release a proposed rule under TSCA section 6 to protect people from the identified risks,” the press release states.

For more information about EPA’s 1,4-dioxane risk evaluation and supplement, visit the agency’s website.