The explosion from a small bomb could flood commuter train tunnels between New York and New Jersey in a matter of hours, according to a new government analysis that suggests the PATH rail system is more vulnerable than initially thought.
The draft analysis, obtained by The New York Times, shows that the PATH system's four tunnels are structurally fragile enough that the damage from a bomb small enough to be carried onto a train could allow 1.2 million gallons of water per minute to gush into a tunnel and flood the system.
About 230,000 people use the PATH system each weekday.
The analysis is characterized as preliminary and continuing. It was based on work by Lawrence Livermore National Laboratory in California and the Rensselaer Polytechnic Institute in Troy. The Times obtained it from a government official it did not identify. According to the paper, the official felt there had been a lack of response to the analysis, which the official said the Port Authority got about three weeks ago.
A spokesman for the Port Authority of New York and New Jersey, which runs the PATH system, defended the system's safety.
"If we believed in any way that passengers were in danger, we'd close the system," spokesman Marc La Vorgna said. "That would happen immediately."
He said Port Authority police recently increased patrols and bag searches in the PATH system, and the agency's board voted last week to spend $180 million to boost security on the rail line.
Aides to New Jersey Gov. Jon S. Corzine and New York Gov. George Pataki would not say whether the governors had seen the new analysis. A spokesman for New York City Mayor Michael Bloomberg declined to comment.
A spokesman for the federal Department of Homeland Security said he was unable to determine whether that agency had been notified, the Times reported.
Concerns have long been raised about potential terrorist attacks on tunnels connecting to New York City. In July, authorities said they had thwarted a suicide-bomb plot involving the PATH tunnels.
The new analysis was based on both computer models and physical tests on cast iron from the tunnels, the Times reported. It describes several steps to lessen the effect of any explosions, including installing floodgates and fortifying critical parts of the tunnels, according to The Times.