Vinyl chloride, a highly toxic and flammable chemical is believed to be leaking into the creek, Petty Officer Nick Ameen told CNN. No casualties have been reported, but some people in the immediate area have been evacuated.
Residents told CNN affiliate WPVI they smelled an odor in the area.
The Coast Guard is not in a search and rescue mode, Ameen said. Coast Guard crews, he said, are heading to the scene to stop the leak and begin cleanup operations.