The North Carolina Department of Environmental Quality’s Division of Water Resources (DWR) has identified elevated 1,4-dioxane levels discharged from the City of Asheboro Wastewater Treatment Plant to Hasketts Creek, which drains to the Deep River within the Cape Fear River Basin. 1,4-Dioxane is categorized by the EPA as a likely human carcinogen, or a substance that likely can cause cancer. See EPA’s Risk Evaluation for 1,4-dioxane. 1,4-Dioxane is used for a variety of industrial purposes.
DWR staff notified downstream drinking water utilities and businesses on Jan. 28 after preliminary laboratory results indicated elevated levels of 1,4-dioxane. Entities notified include the City of Sanford, Fayetteville Public Works Commission, Harnett Regional Water, Pender County Utilities, Cape Fear Public Utility Authority in Wilmington, Bladen Bluffs Water System, Pilgrim’s Pride Water System in Sanford and International Paper Co.
DWR detected elevated levels of 1,4-dioxane in a sample collected on Jan. 24, 2025, from the City of Asheboro’s wastewater treatment plant discharge, returning a final concentration of 2,200 parts per billion (ppb). The Asheboro Wastewater Treatment Plant detected a concentration of 3,520 ppb from their own sample, which was also collected on Jan. 24. After the initial analysis of the samples, DWR completed quality assurance and control measures to validate the results. DEQ, using EPA toxicity calculations for lifetime exposure, has determined that the average monthly 1,4-dioxane concentration protective of downstream water supplies is about 22 ppb for the Asheboro discharge.
The concentrations of 1,4-dioxane were measured in "grab samples," or wastewater samples taken at a single point in time by the facility and DWR. For 1,4-dioxane, the grab samples are performed using an U.S. Environmental Protection Agency-certified test method.
Monitoring is also being performed at other wastewater treatment plants identified to have 1,4-dioxane in their discharge to the Cape Fear River Basin, including Burlington, Greensboro, High Point and Reidsville. Significant reductions have occurred at some wastewater treatment plants through a collaborative effort with the Environmental Management Commission, DEQ and municipal operators. DEQ will continue to work with the EMC to seek further reductions in 1,4-dioxane discharges.
In August 2023, DWR included 1,4-dioxane permit limits in Asheboro’s National Pollutant Discharge Elimination System (NPDES) permit. In September 2024, the North Carolina Office of Administrative Hearings issued an order striking these limits from the permit. DEQ has appealed that ruling, and EPA has objected to the ruling’s removal of the 1,4-dioxane limits from permit. The primary means to achieve health-based levels is to reduce and minimize the release of the contaminant at the sources. Industrial best management practices and treatment technologies exist to achieve these outcomes that protect North Carolinians’ drinking water sources.
DWR has posted 2024 and 2025 sampling data online and will continue to update the data as it becomes available: Cape Fear River Basin 1,4-Dioxane Wastewater Discharge Data.