2023-15846: 1,4-Dioxane; Draft Revision to Toxic Substances Control Act (TSCA) Risk Determination; Notice of Availability and Request for Comment

Summary

The Environmental Protection Agency (EPA) is announcing the availability of and requesting public comment on a draft revision to the risk determination for 1,4-dioxane following a risk evaluation issued under TSCA. EPA published a risk evaluation for 1,4-dioxane in December 2020 and a draft supplement to the risk evaluation in July 2023. This draft revision to the 1,4-dioxane risk determination reflects policy changes announced in June 2021, to ensure the public is protected from unreasonable risks from chemicals in a way that is supported by science and the law, as well as information from the 2023 Draft Supplement to the risk evaluation. In this draft revision to the risk determination EPA has preliminarily determined that 1,4-dioxane, as a whole chemical substance, presents an unreasonable risk of injury to health when evaluated under its conditions of use. This draft risk determination considers the occupational and consumer exposures from the December 2020 Risk Evaluation, as well as the occupational, general population, and fenceline community exposures in the draft supplement to the risk evaluation, including exposures that result from conditions of use where 1,4-dioxane is present due to production as a byproduct and the risks from general population and fenceline communities' exposures to 1,4-dioxane released under the conditions of use to drinking water sourced from surface and ground water and ambient air. In addition, this revised risk determination does not reflect an assumption that all workers always appropriately wear personal protective equipment (PPE). EPA understands that there could be adequate occupational safety protections in place at certain workplace locations; however, not assuming use of PPE reflects EPA's recognition that unreasonable risk may exist for subpopulations of workers that may be highly exposed because they are not covered by Occupational Safety and Health Administration (OSHA) standards, or their employers are out of compliance with OSHA standards, or because many of OSHA's chemical- specific permissible exposure limits largely adopted in the 1970's are described by OSHA as being "outdated and inadequate for ensuring protection of worker health," or because EPA finds unreasonable risk for purposes of TSCA notwithstanding OSHA requirements. This revision, when final, would supersede the condition of use-specific no unreasonable risk determinations in the December 2020 1,4-dioxane risk evaluation (and withdraw the associated order) and would make a revised determination of unreasonable risk for 1,4-dioxane as a whole chemical substance.

The agency’s own summary, as published.