A North Carolina Superior Court has upheld state regulators’ authority to impose wastewater discharge limits on the industrial solvent 1,4-dioxane, reinforcing regulators’ ability to restrict emerging toxic contaminants as a separate high-profile lawsuit over a tire-derived chemical awaits a federal ruling in California.
The February 5 decision by Wake County Superior Court found that the North Carolina Department of Environmental Quality (DEQ) acted within its authority when establishing discharge permit limits for 1,4-dioxane in wastewater from the City of Asheboro. The chemical is often used as a solvent in manufacturing applications, and may be found in soaps and detergents. The ruling reversed a 2024 Office of Administrative Hearings decision that had removed the limits from Asheboro’s wastewater discharge permit.
In its decision, the court concluded that DEQ followed proper state and U.S. Environmental Protection Agency protocols in developing the permit limits and had created criteria intended to protect public health.
“Because 1,4-dioxane is a pollutant likely to cause cancer in humans, permit limits are necessary to protect North Carolinians’ drinking water and their health,” said DEQ Secretary Reid Wilson in a statement. “The court order vindicates DEQ’s decision to impose limits to protect downstream communities from this harmful carcinogen.”
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State regulators previously identified elevated levels of 1,4-dioxane in discharges from Asheboro’s wastewater treatment plant. The chemical, an industrial solvent used in various manufacturing and commercial applications, has been detected in wastewater and surface waters across multiple river basins, including the Cape Fear River Basin.
DEQ has monitored municipal wastewater discharges and surface waters across 15 river basins to identify sources of the contaminant. Data collected in 2024 and 2025 documented the detection of 1,4-dioxane in wastewater effluent from certain treatment facilities.
North Carolina Attorney General Jeff Jackson said the ruling reinforces the ability of regulators to prevent contamination of drinking water sources.
“This case is about preventing toxic pollutants from contaminating the rivers that North Carolinians rely on for clean drinking water,” Jackson said. “The Superior Court was right to uphold DEQ’s ability to limit chemicals in our water, and my office will continue working with DEQ to make sure people have clean drinking water.”
