EPA Identifies 1,4-Dioxane as an Unreasonable Risk to Human Health

The U.S. Environmental Protection Agency (EPA) has released its final supplement to the risk evaluation of 1,4-dioxane, concluding that the solvent presents an unreasonable risk to human health. The compound, found in industrial applications, consumer products like dish soaps and laundry detergents, and water sources, has been linked to cancer, liver toxicity, and adverse effects on nasal tissue.

Unreasonable Risk to Human Health

1,4-Dioxane, a solvent used in laboratories, cleaning products, and various industrial processes, is also a byproduct in the production of several chemicals. The final supplement to the EPA’s 2020 risk evaluation addresses significant gaps, including the risks of exposure through drinking water and air, as well as combined exposures from multiple sources.

While 1,4-dioxane was one of the first chemicals to undergo review under the amended Toxic Substances Control Act (TSCA), earlier evaluations did not fully account for general population exposure or risks to vulnerable groups, such as those in fenceline communities.

EPA’s Findings on Uses and Exposure

The EPA’s final evaluation finds that 1,4-dioxane poses an unreasonable risk primarily to workers handling the substance in manufacturing and commercial settings. The chemical also presents risks to the general population, especially those living near industrial sites or relying on contaminated water sources.

Water contamination occurs when industrial discharges or consumer products containing 1,4-dioxane are washed down the drain, ultimately contaminating drinking water supplies. Fenceline communities, people with underlying health conditions, and vulnerable populations are at higher risk from these exposures.

Environmental Impact and Next Steps

The EPA determined that 1,4-dioxane does not pose an unreasonable risk to the environment. However, the agency has initiated the next phase of risk management to mitigate the health hazards associated with the chemical. This includes releasing a proposed rule under TSCA section 6 to implement protective measures.

Additionally, the EPA is coordinating with other agencies, including the Office of Water (OW), to evaluate the potential for regulatory actions under the Safe Drinking Water Act (SDWA) to address 1,4-dioxane contamination in water.
The agency is committed to reducing the risk posed by 1,4-dioxane and will continue working on further actions to protect public health.