A section of a freight train carrying toxic chemicals fell into a creek in New Jersey on Friday when a bridge collapsed, but there was no serious spill, officials said.

Authorities near Paulsboro, New Jersey, said the accident occurred early in the morning, causing seven train cars to derail and sending three into the water.

Part of the train was carrying vinyl chloride, which is used to make PVC plastic, and other industrial chemicals, the Coast Guard said.

"Authorities are in the process of assessing what materials have been spilled from any damaged container cars," the Coast Guard said in a statement.

"Local authorities have evacuated the area in a half-mile radius. A one-mile safety zone on the water to the north and south of the bridge has been established," the Coast Guard added.

Larry Ragonese, spokesman for New Jersey's environmental health department, told AFP there was no serious danger.

"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," he said. "It's really a minimal environmental or health issue at this point."

According to Ragonese, 22 people went for doctor's check-ups but there were only "minor" injuries.