The latest pictures appear to show that workers have used booms to set up a perimeter in the waters of the Mantua Creek to contain any chemical spill.
Schoolchildren in the vicinity are being allowed to leave schools to go home, according to local broadcaster WCAU.
The road leading to the town of Paulsboro has been reopened but a limited evacuation is still in force.
The Coast Guard told WCAU that there is no immediate threat.
This photo shows at least four tanker carriages at least partly submerged in the creek in New Jersey.
A number of other carriages - not all of the kind that is used for transporting liquids or gases - appear to have been derailed when the bridge collapsed.
The report in the South Jersey Times said that 11 people were taken to Underwood-Memorial Hospital in Woodbury for "decontamination and treatment".
A further 17 people made their own way to the hospital complaining of respiratory problems, it said.
The South Jersey Times cites the Gloucester County Freeholder director Robert Damminger - a local official - who confirmed that at least one of the carriages contained vinyl chloride.
It also quote county officials as saying that an environmental clean-up firm is attempting to place booms in the waterway to contain the spill.
Authorities have evacuated a half-mile (805-metre) area around the chemical spill and the waterway was closed as well.
The US Coast Guard is working with the state Department of Environmental Protection to assess the situation.
At least 18 contractors working in the area near a chemical leak have complained of respiratory distress, police said, adding that residents in the area had been advised to remain indoors, with their windows shut.
Residents near the chemical leak in the US are being evacuated and schools are in lockdown, according to the South Jersey Times.
Rescue workers who were exposed to the vapors are being sent to a local hospital for treatment and decontamination if needed, the newspaper added.
Paulsboro school Superintendent Frank Scambia, told the local paper:
We locked down which means all the kids are in the gym there (at the high school). Nobody is allowed in or out.
A train in New Jersey has derailed causing hazardous chemicals to spill, including vinyl chloride.
Short-term exposure to high amounts of that chemical can lead to dizziness, drowsiness and headaches, according to the Environmental Protection Agency.
A rail bridge collapsed over a creek in southern New Jersey, causing a freight train to derail and to spill hazardous chemicals, police said.
The incident occurred in Paulsboro, New Jersey, at a crossing near the Delaware River, police said. Paulsboro is just over the river from Philadelphia.