EPA Releases Meeting Minutes and Final Report from Science Advisory Committee on Chemicals 1,4-Dioxane Review

Released November 17, 2023

Today, EPA released the meeting minutes and final report from the September 12-14, 2023, Science Advisory Committee on Chemicals (SACC) virtual public meeting regarding the Draft Supplement to the Risk Evaluation for 1,4-Dioxane.

1,4-Dioxane was one of the first 10 chemicals to undergo risk evaluations under the amended Toxic Substances Control Act (TSCA). The risk evaluation for 1,4-dioxane was finalized in December 2020.

In June 2021, EPA announced policy changes surrounding the risk evaluations conducted under the previous administration, including 1,4-dioxane. These risk evaluations excluded air, water and disposal as potential exposure pathways to the general population and potentially exposed or susceptible subpopulations, including fenceline communities (i.e., communities near industrial facilities). 

In order to address these oversights in the 1,4-dixoane risk evaluation, EPA released for public comment and review the draft supplement to the 2020 risk evaluation earlier this year. The draft supplement considers additional exposure pathways and risks that were excluded from the published 2020 risk evaluation. While the 2020 risk evaluation identified health risks to workers, occupationally exposed non-users, consumers, bystanders, and the general population, it did not evaluate general population exposures to 1,4-dioxane in drinking water or air and exposure to 1,4-dioxane generated as a byproduct. The draft supplement also estimates risks from aggregate exposures from multiple facilities located in the same area and risks to people living in fenceline communities (in accordance with TSCA’s requirement to evaluate risk to potentially exposed or susceptible subpopulations).

EPA sought external peer review from the SACC on issues related to environmental release from industrial sources, application of occupational exposure modeling approaches and monitoring data for industrial and commercial operations, sources of environmental releases from hydraulic fracturing operations, modeling concentrations of 1,4-dioxane in surface water and groundwater, and exposure from multiple sources of 1,4-dioxane in air or water.

The meeting minutes and final report are available in docket EPA-HQ-OPPT-2022-0905 on regulations.gov and through the SACC webpage for the 1,4-dioxane meeting.

The SACC serves as one of several scientific peer review mechanisms of EPA’s Office of Chemical Safety and Pollution Prevention. It provides independent scientific advice and recommendations to EPA on the scientific basis for risk assessments, methodologies and pollution prevention measures and approaches for chemicals regulated under TSCA.   

For additional information, contact the Designated Federal Official, Dr. Alaa Kamel at kamel.alaa@epa.gov.