A group of Parkersburg residents is asking a federal appeals court for permission to pursue its effort to collectively press a water contamination lawsuit against DuPont.

Thousands of Parkersburg residents want to sue DuPont. They claim the city's water was contaminated by a chemical the company uses at a nearby plant to manufacture Teflon.

Last month a federal judge ruled the residents could individually sue DuPont, but he couldn't certify the case for class-action status on the basis of potential harm.

DuPont has already settled a 2001 class-action case involving the chemical C8 with residents living in six water districts near DuPont's Washington Works plant.

The request was filed with the 4th Circuit Court of Appeals on Wednesday.