Emergency crews responded Wednesday to a hazmat incident in the Delaware River in Delaware County.TINICUM TWP., Pa. (WPVI) -- Emergency crews responded Wednesday to a hazmat incident in the Delaware River in Delaware County.Crews were called to the river off Jansan Avenue in Tinicum Township around 5 p.m. Officials discovered an oil sheen along the river.Officials do not believe it came from any of the refineries.DEP and U.S. Coast Guard crews are investigating.