Defending cities against dirty bombs is difficult

know that before New Year’s eve, hundreds of local, state, and federal agents fanned out on highways and other approaches to Manhattan searching for radiation signatures. Officers scanned warehouses, garages, and other buildings as much as eighty miles away. On 31 December, authorities also set up checkpoints and monitored radiation sensors deployed on bridges, tunnels, boats, and waterways around the island. In addition to conducting periodic aerial screening, New York police routinely set up checkpoints twice a day on Manhattan roadways as a defensive, training, and deterrence measure. Note that on the day the helicopter search failed, a ground unit operating three kinds of vehicle sensors successfully detected the test sport-utility vehicle carrying cesium-137 on 42nd Street near Eighth Avenue, close to Times Square.

Independent experts warn, though, that existing detectors are far less capable of finding an improvised nuclear bomb with lead-shielded, weapons-grade uranium, which would emit a much smaller radiation signal. Policymakers in Washington regard that as a far more serious threat than dirty bombs. New York worries just as much about the latter, and believes the program can provide an effective defense. Falkenrath said the New York system still has three pressing needs: better detection technology to find the most dangerous and shielded devices; better communications and data transfer links for managing monitoring efforts; and better procedures allowing police officers to investigate all alarms without disrupting traffic, which they can do in Manhattan but not on the approaching highways. “It’s a difficult thing to do, and I’ll be frank about it…. It requires really constant vigilance and effort to maintain it,” Falkenrath said. “Certainly, if this model goes nationwide, they need a lot more help, because most other parts of the country are not going to have the ability to devote these sorts of resources” without cutting into everyday crime-fighting.

Hsu writes that New York paid the Department of Energy (DOE) $800,000 in 2005 to map background radiation sources in the city — a critical baseline requirement for detection efforts. The survey found eighty unexpected hot spots, including a public park on Staten Island which was subsequently shut down. The DHS and the DOE were told to advertise their capability to other cities. So far, only Chicago and Washington have expressed interest, Oxford said. The office that oversees Securing the Cities was created in 2006 with the support of Vice President Cheney, and its $485 million 2008 budget is the largest part of the DHS’s shrinking research portfolio, which includes aviation security, explosives and bio-defense. Its efforts, though, have hit turbulence. DHS secretary Michael Chertoff in October delayed the deployment of as much as 1,400 advanced spectroscopic portal radiation detectors as part of a $1.2 billion program announced in July 2006 to screen trucks, cars, and cargo containers at border crossings and ports. Congress withheld funds this year to buy the $377,000 machines following concerns about the DHS’s cost-benefit analysis used to justify their development.