A local environmental group says video footage shows pollution coming from hydraulic fracturing -- or fracking -- sites throughout the region.
Tom Pelton, who conducted the investigation for the Chesapeake Bay Foundation, says he and a videographer visited 15 sites in Pennsylvania, Maryland and West Virginia, and found emissions at 11 locations.
"We hired a videographer who normally works for the oil and gas industry, and he has special infrared camera that he uses to detect gas leaks," he says.
Pelton says the group has sent the footage to the EPA, which is studying the practice.
"It's doing a study of ground water, but we want them to do something broader than that. We want them to look at air pollution," he says.
Fracking refers to the injection of water, sand and chemicals into shale formations so that cracks form and gas escapes. And while critics are concerned about increased pollution, advocates say fracking creates jobs while producing less carbon than coal.