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EPA Releases Supplemental Analysis to the Draft Risk Evaluation for 1,4-Dioxane for Public Comment

For Release: November 19, 2020

EPA is asking for public input on a supplemental analysis to the draft risk evaluation for 1,4-dioxane.

After releasing the draft risk evaluation in June 2019, in response to public comments and feedback from peer reviewers EPA conducted a supplemental analysis to the draft risk evaluation. This supplemental analysis to the draft risk evaluation includes eight consumer uses, like surface cleaners, laundry/dishwashing detergents, and paint/floor lacquer, where 1,4-dioxane is present as a byproduct, meaning when 1,4-dioxane is created from the breakdown of other chemicals. The supplemental analysis also assesses exposure to the general population from 1,4-dioxane in surface water.

In the supplemental analysis to the draft risk evaluation, EPA preliminarily found no unreasonable risk to consumers from the eight conditions of use assessed. The agency also preliminarily found no unreasonable risks under any of the conditions of use to the general population from exposure to 1,4-dioxane.

Because these additional conditions of use and exposure pathways were not included in the draft risk evaluation, the agency is providing an opportunity for the public to give input on the supplemental analysis and risk determinations before the risk evaluation is finalized. EPA will accept public comments on the supplemental analysis to the draft risk evaluation in docket EPA-HQ-OPPT-2019-0236 for 20 days.

EPA will use feedback received from the public comment process to inform the final risk evaluation. The supplemental analysis to the draft risk evaluation is not a final agency action and represents the agency’s current review of the scientific information on this chemical.

View the 1,4-dioxane supplemental analysis to the draft risk evaluation and supporting documents.


TSCA is our nation’s primary chemical management law. This law requires EPA to evaluate the risks associated with exposure to existing chemicals using the best available science then take action to manage any unreasonable risks identified.

1,4-Dioxane, one of the first ten chemicals to undergo risk evaluation, is used primarily as a solvent in a variety of commercial and industrial applications like in the manufacture of other chemicals, as a processing aid, a laboratory chemical, and in adhesives and sealants. The chemical is also a byproduct in some consumer products such as soaps and detergents.

Learn more about the risk evaluation process required by TSCA.