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Assessing and Managing Chemicals under TSCA

Risk Evaluation for 1,4-Dioxane

EPA evaluated 1,4-dioxane under the amended Toxic Substances Control Act (TSCA) and completed the final risk evaluation in December 2020. EPA will now begin the process of developing ways to address the unreasonable risks identified and has one year to propose and take public comments on any risk management actions.

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Uses of 1,4-Dioxane

1,4-dioxane is currently used as a solvent in a variety of commercial and industrial applications such as in the manufacture of other chemicals, a processing aid, functional fluid, a laboratory chemical, in adhesives and sealants, in spray polyurethane foam, in printing inks, and as a dry film lubricant. 1,4-dioxane may be found as a contaminant in consumer products such as soaps and detergents. Information from the 2016 Chemical Data Reporting (CDR) for 1,4-dioxane indicates reported production volume in more than 1.1 million lbs/year (manufacture and import).

Risk Evaluation of 1,4-dioxane under Amended TSCA

In December 2020, EPA released the final risk evaluation for 1,4-dioxane. The final risk evaluation shows that there are unreasonable risks to workers and occupational non-users from 13 conditions of use. EPA found no unreasonable risks to the environment, consumers, bystanders, or the general population. As with any chemical product, EPA strongly recommends that users carefully follow all instructions on the product’s label.

In June 2019, EPA released the draft risk evaluation for 1,4-dioxane for public comment and peer review. In November 2020, EPA released a supplemental analysis to the draft risk evaluation which includes eight consumer uses 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 June 2017, EPA released the scope document for 1,4-dioxane which includes the hazards, exposures, conditions of use, and the potentially exposed or susceptible subpopulations EPA expects to consider in its risk evaluation of 1,4-dioxane conducted pursuant to TSCA section 6(b). In June 2018, EPA released the problem formulation for 1,4-dioxane which refined the scope of the 1,4-dioxane risk evaluation by clarifying the chemical uses that EPA expected to evaluate and describing how EPA expected to conduct the evaluation. 

After releasing the scope documents for each of the first 10 chemicals undergoing risk evaluation under TSCA, the dockets for each of these first 10 chemicals were open for public comments. Read EPA’s Responses to Public Comments Received on the Scope Documents for the First Ten Chemicals for Risk Evaluation under TSCA. This document addresses public comments received in response to the scope document.

Review of 1,4-Dioxane Prior to Amended TSCA

Prior to the Frank R. Lautenberg Chemical Safety for the 21st Century Act, EPA began the review of 1,4-dioxane and published the following information.