Regulatory Updates & Funding Options for Municipalities and Utilities

The regulatory landscape for 1,4-dioxane is rapidly evolving. In July of 2023, the U.S. Environmental Protection Agency (EPA) released the 2023 Draft Revised Risk Determination for 1,4-dioxane and the 2023 Draft Supplement to the Risk Evaluation for 1,4-dioxane, finding the chemical presents an unreasonable risk of injury to human health.

In November 2024, EPA released the final revised risk determination for 1,4-dioxane under the Toxic Substances Control Act (TSCA), indicating that it presents an unreasonable risk of injury to human health under the conditions of use, from cancer and non-cancer risks to workers and occupational non-users, and cancer risks to the general population. EPA stated that it will propose risk management regulatory actions to the extent necessary so that 1,4-dioxane no longer presents an unreasonable risk to health. In addition, EPA specifically determined that 1,4-dioxane in drinking water sources from surface water contaminated with industrial discharges and down-the-drain disposals of commercial and consumer products contribute to the unreasonable risk from 1,4-dioxane. The risk determination will likely influence further regulatory action at the state level as well.

To date, the following state-level initiatives are in place:

• 39 states have health-based advisories in place for the contaminant.
• New York State established a Maximum Contaminant Level (MCL) for 1,4-dioxane, set at 1 ppb.
• California, New Jersey, Illinois, and Virginia are in the process of developing MCLs.