Greensboro officials believe they have found a potential source for a contaminant in the city's drinking water in an area near Piedmont Triad International Airport.
The ingredient is called Perfluorooctanesulfonic acid, or PFOS, and is primarily known for its use in stain repellents.
But it can also be used in a synthetic foam firefighters use to control fuel-based fires. City officials say they've found a place near the airport where it was used to do just that.
The News and Record reports PTI also conducts fire-training drills using firefighting foam once a year on its runway. Runoff from those drills could have ended up in a nearby stream or in groundwater.
Airport officials say if the city's analysis points to the tests contributing to contamination and it's necessary to clean it, the airport will develop a strategy for doing so.