A rail bridge has collapsed over a creek in New Jersey causing a freight train to derail and spill hazardous chemicals.
Police said vinyl chloride, a highly toxic and flammable industrial chemical, was spilling from at least one of the Conrail cars that derailed in Paulsboro at a crossing near the Delaware River.
Seven cars derailed and three fell into Mantua Creek. Some 22 people were checked by a doctor, many for breathing problems, but there were only "minor" injuries.
Larry Ragonese, spokesman for New Jersey's environmental health department, said: "Several cars had vinyl chloride and only one of those cars went into the water and lost some of its cargo and released some of the vinyl chloride into the air.
"That vinyl chloride has dissipated at this point. It's really a minimal environmental or health issue at this point."
Residents in the area were advised to remain indoors, with their windows shut.
The US Coast Guard said in a statement: "Authorities are in the process of assessing what materials have been spilled from any damaged container cars."
Television images of the scene showed several cars partly submerged in the creek.
One car was shown at a near-vertical angle from the bridge bed into the water.
Conrail is jointly owned by rail operators CSX Corp. and Norfolk Southern Corp.