Thanks For Doing Nothing At All To Make Us Feel Any Less Vulnerable This Christmas

After early reports of a terror plot to blow up the PATH tunnels leading into Lower Manhattan seemed to downplay the extent of destruction that could be inflicted, officials now admit that the tunnels are actually pretty vulnerable:

An analysis done for the Port Authority of New York and New Jersey says that the PATH train tunnels under the Hudson River are more vulnerable to a bomb attack than previously thought, and that a relatively small amount of high explosives could cause significant flooding of the rail system within hours.

The analysis, based on work by Lawrence Livermore National Laboratory and the Rensselaer Polytechnic Institute, revises some critical aspects of an assessment of the system’s vulnerability that was presented to the agency last spring. It makes clear that the tunnels — four tubes of varying design and sturdiness that stretch across the Hudson riverbed — are structurally more fragile than first thought.

A draft summary of the most recent analysis was given to The New York Times by a government official who was troubled by what the official felt was a lack of action in response to the analysis, which the official said the Port Authority got about three weeks ago. The official said the latest analysis indicates that it would take only six minutes for one of the PATH tubes to flood if a significant but not necessarily very large bomb were detonated.

. . .

The analysis appears to be the most detailed and sophisticated government review of the train tubes’ vulnerability. Initial findings were shared last May with some members of the agency, but were not made public, and further tests were ordered. More tests are being done in an effort to come up with the best way to strengthen the tunnels.

The Hudson River tubes of the PATH system, which suffered serious damage in the 2001 terror attack, are more vulnerable than most other tunnels that pass under the city’s waterways because they lie in the soft riverbed, unlike other tunnels that are bored through the underlying bedrock. Silt over years has built up atop the tubes, which were laid roughly 90 years ago, but they are not in bedrock.

Several city subway tunnels beneath the East River are in many ways similar to the four PATH tunnels — essentially cast-iron tubes that run along the riverbed. An official at the Metropolitan Transportation Authority said that agency is working on an analysis of its tubes.

The PATH analysis, which is characterized as preliminary and continuing, examines the three different types of PATH tubes under the Hudson. Roughly three-quarters of the tubes’ total length is made of unlined cast iron, with the balance made from concrete-lined cast iron or brick. Many of the details of the analysis — including the size of the bombs under discussion, their placement and the exact nature of the vulnerability — are being withheld by The Times.

The worst case included in the analysis suggests that a bomb that could be easily carried aboard a train could punch a 50-square-foot hole in one side of a tube, possibly breaching both sides of the tunnel. Under that situation, 1.2 million gallons of water a minute could pour into the tunnel, flooding parts of the system in a matter of hours.