EPA releases final risk evaluation for 1,4-dioxane

Washington — The potentially carcinogenic chemical substance 1,4-dioxane presents an unreasonable risk to workers under certain conditions, according to a final risk evaluation recently released by the Environmental Protection Agency, which is now compelled to propose within one year regulatory action to mitigate the chemical’s hazards.

Often used in consumer products, 1,4-dioxane is among the first 10 chemicals under evaluation for potential health and environmental risks under the Frank R. Lautenberg Chemical Safety for the 21st Century Act.

EPA previously found 1,4-dioxane was “likely to be carcinogenic to humans,” a determination shared by NIOSH, the International Agency for Research on Cancer, the National Toxicology Program and others.

Although the final risk evaluation claims the substance offers no unreasonable risk to occupational nonusers or the environment, 1-4-dioxane appears on the Contaminant Candidate List of the Safe Drinking Water Act of 1974. New York considers 1-4-dioxane an “emerging contaminant” and in 2020 became the first state to regulate the substance by establishing a maximum contaminant level in drinking water.

Released by EPA on Dec. 31 and announced in a notice published in the Jan. 8 Federal Register, the final evaluation states 1,4-dioxane poses unreasonable risks to workers engaged in operations including:

• Domestic manufacturing
• Pharmaceutical, medicine and basic organic chemical manufacturing
• Uses as an adhesive and sealant
• Printing and printing compositions
• Disposal

As required under the Toxic Substances Control Act, which the Lautenberg Act amended, EPA must address risks by proposing within one year regulatory actions such as training, certification, restricted access and/or ban of commercial use, and then accept public comment on any proposals.

“EPA generally assumes compliance with OSHA requirements for protection of workers, including the implementation of the Hierarchy of Controls,” the final evaluation states.