The bridge collapsed in November as a freight train was crossing, derailing eight cars. A tank car punctured in the accident leaked 20,000 gallons of vinyl chloride into a creek, which combined with the water to create a dangerous gas cloud.
National Transportation Safety Board officials said at Tuesday's investigative hearing that local police and fire officials who responded to the spill didn't follow safety standards, creating greater exposure to the gas for first responders and some residents.
The hearing focused first on the bridge problems. Mark Mather, a Conrail engineer, described how train engineers were regularly reporting problems with the moveable bridge, especially its locking mechanism, before it collapsed on Nov. 30. He said he often crossed the bridge twice a day and that the frequency of the problems increased noticeably after Hurricane Sandy ravaged the region.
NTSB officials said Conrail has disclosed 24 trouble reports in the year before the collapse, about half of which occurred after the October storm.
"I think the number is far greater than that, far greater," Mather said. Not only did he experience problems with the bridge, but other crews frequently told him about problems they were experiencing, he said.
Tim Tierney, Conrail's chief engineer, insisted there were no more than 24 in the weeks between the storm and the collapse. Each time there was a problem, he said, the company would send workers to check on the bridge and they wouldn't leave until the problem was fixed.
The swing bridge allows trains to cross when closed and boats to pass when open.
According to NTSB, the train crew arrived to find the bridge apparently closed, but with a red stop signal displayed. The crew stopped the 82-car train and repeatedly signaled the bridge to close in an effort to get a green signal, but the control system didn't respond. The crew notified the dispatcher that the conductor had inspected the track and concluded the bridge was closed. The dispatcher gave the crew authority to operate the train past the red signal. Shortly after that, the train derailed.
NTSB said it was holding the hearing to gather more information for its accident investigation. The board holds hearings only a few times at year at most, reserving them mainly for accidents with significant safety implications.
"There is always some risk when large quantities of hazardous materials are transported through sensitive areas," NTSB Chairman Chris Hart said. "It is important to understand if there are the right safeguards for those risks and if the training keeps up with the multitude of potential threats from hazardous materials releases."
NTSB investigators said fire officials set up a command post 50 yards from the accident scene even though safety standards call for it to be positioned in a safe area. It remained that way until the afternoon hours, until it was moved farther away.
Police and firefighters also didn't initially wear protective breathing apparatuses as they walked through the accident scene or the gas cloud.
Emergency response procedures for such circumstances recommend an initial downwind evacuation of a half mile and instruct first responders to stay clear of vapors, investigators said. About 30 minutes after the derailment, the police ordered a mandatory evacuation of a three-block area, investigators said. Some nearby residents were initially told to leave, but later others were told to stay indoors with the windows closed, they said.
Twenty-three residents were treated at nearby hospitals for possible vinyl chloride exposure, the safety board said. The train conductor and many other emergency responders were also exposed.
As of last month, the emergency response and cleanup costs totaled about $28.2 million, the board said.