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Assessing and Managing Chemicals under TSCA

Risk Evaluation for 1,4-Dioxane

1,4-Dioxane is currently undergoing risk evaluation under the Toxic Substances Control Act (TSCA). EPA is evaluating 1,4-dioxane because the 2016 amendments to TSCA directed EPA to pick its first 10 chemicals for evaluation from the TSCA Work Plan, and 1,4-dioxane is on the Work Plan. In June 2019, EPA released the draft risk evaluation for 1,4-dioxane.

It is important to note that for the general population, including children, environmental statutes administered by EPA such as the Clean Air Act, the Safe Drinking Water Act, the Clean Water Act, and the Resource Conservation and Recovery Act, adequately assess and effectively manage risks from 1,4-dioxane. In the draft risk evaluation for 1,4-dioxane, EPA did not find unreasonable risk to the environment. The data in the draft risk evaluation for 1,4-dioxane does show there could be unreasonable risks to workers in certain circumstances. These initial determinations may change as our assessment becomes more refined through the public and peer review process.

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Chemical Description of 1,4-Dioxane

1,4-Dioxane 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. While 1,4-dioxane is a likely human carcinogen and does not readily biodegrade in the environment, it is unlikely that most people would be exposed to this chemical which means that potential risks from this chemical are low. No consumer uses for 1,4-dioxane were reported in the U.S. in the 2016 Chemical Data Reporting (CDR), and EPA has not identified any information indicating consumer uses. 2016 CDR data shows that there were two manufacturers producing or importing 1,059,980 pounds of 1,4-dioxane in the U.S. in 2015.

Uses Included in the Risk Evaluation, Problem Formulation,and Scope

In the draft risk evaluation, EPA looked at 14 conditions of use associated with the manufacturing (including import), processing, distribution, use, and disposal of 1,4-dioxane, including the following:

  • Processing aids (not otherwise listed) (270,000 lbs.)
  • Functional fluids in open and closed systems (<150,000 lbs.)
  • Laboratory chemicals (<150,000 lbs.)
  • Adhesives and sealants (professional film cement)
  • Spray polyurethane foam
  • Printing and printing compositions
  • Disposal of waste materials containing 1,4-dioxane
  • Dry film lubricant

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 the 1,4-dioxane conducted pursuant to TSCA Section 6(b)(4). 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, the dockets for each of the 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 cross-cutting public comments received in response to EPA publishing the scope documents.

Draft Risk Evaluation

In June 2019, EPA released the draft risk evaluation for 1,4-dioxane. The public comment period for the draft risk evaluation has closed.

Review Prior to the Lautenberg Act

Prior to the Lautenberg Act, EPA began the review of 1,4-dioxane and published the following information.