The chemical did not come from the new $23 million building where it is produced but from a leaking cement cistern the company no longer uses, company officials said.
The chemical, ammonium perfluorooctanoate or APFO, is used to produce Teflon and similar products. The chemical was first found in trace levels in 2003 and also was detected at trace levels in DuPont wastewater discharged into the Cape Fear River, said Larry Stanley, a hydrogeologist for the state Division of Waste Management.
DuPont notified the state of the contamination and the state is allowing the company to oversee additional testing for the chemical, Stanley said.
The chemical is commonly known by its trademarked name, C8, and is the same chemical that contaminated public water supplies around a DuPont plant in West Virginia. The contamination led to a class-action lawsuit involving more than 50,000 people.
The U.S. Environmental Protection Agency is investigating the chemical because it persists so long in the environment.
DuPont began manufacturing APFO in Fayetteville in 2002 after its creator, the chemical company 3M, stopped producing it for environmental reasons.
DuPont's Fayetteville Works plant is the only facility in the United States that makes the chemical.