Officials say there is no risk from an early-morning train derailment that sent thousands of gallons of chemical vapor into the air in Paulsboro, Gloucester County.

But it could be several days before the train cars are removed and the Conrail-owned train line to reopen, as they await a heavy crane that must travel from New York Harbor to the waters of the Mantua Creek near the Delaware River near Philadelphia.

John Enright, a Conrail spokesman, said the company was cooperating with all local, state and federal authorities and its first concern is public safety.

"We very much regret the impact to the local community," he said.

The train has two locomotives, 82 rail freight cars, and a caboose, and was crossing the bridge when four cars derailed at about 7 a.m. Friday, said Assemblyman John Burzichelli, the incident commander at the scene. The train originated in Camden was headed to the DuPont's Carneys Point plant.

One car, a 32,000 gallon capacity tanker carrying 25,000 gallons of vinyl chloride in gas form, was breached at about its midpoint. The chemical vaporizes and disperses into the air when it comes into contact with the atmosphere, and whatever was left in the tank self-refrigerated in contact with the water and is in a slushy mix at the bottom of the tank, said Gloucester County EMS director Tom Butts.

Officials stressed that the tank is not leaking, though booms were placed in the creek water around the site to catch any fluid from the train. Contact with the chemical vapor can cause dizziness and nausea. As of 3 p.m. 71 people sought medical treatment at Underwood Memorial Hospital in Woodbury and eight remain hospitalized in stable condition.

"The product in the cars is very heavy and will sink to the bottom," he said. A damage assessment of the entire train, which was also carrying lumber and plastic pellets, is ongoing, he said.

"This is going to be a several-day operation," Butts told reporters gathered at the Paulsboro Fire House.

It's unclear yet whether the derailment caused the bridge to fail, or if the bridge collapsed first. Investigators from the National Transportation Safety Board are en route from Washington, DC and are expected to make another briefing at 3 p.m.

New Jersey State Senator Steve Sweeney said while the train line is privately owned, it is under the jurisdiction of federal and state authorities. The same bridge was the site of an incident in 2009, and Sweeney said the rail agency did the repair work in house.

"There's a lot of jobs that are on the either end of these (train) stops," Sweeney said. He said the county recently secured $18 million in federal Department of Transportation funding to repair bridges, but that wouldn't have helped here.

"People have no idea how bad the rail infrastructure is in this county," Sweeney said.

By 1 p.m., the site was declared safe, local roads were open and things were getting back to Normal in this rural-industrial Gloucester County community. Still, a state Department of Environmental Protection van would patrol the area around the site taking air samples, said DEP spokesman Larry Hajna.