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"Revelation" – Dirty Bomb Vulnerability

While admitting that the likelihood of a nuclear attack on a U.S. remains low, officials admit that they are not zero. But, we are finding out that defending cities against dirty bombs is difficult. That’s the conclusion reached by the Department of Homeland Security after an NYPD helicopter fashioned with sensitive radiation detection equipment flew over Lower Manhattan in December. The fly over was actually a block-by-block hunt to find a black SUV in the Wall Street area carrying the components of a homemade radiological dirty bomb. As written by The Washington Post's Spencer Hsu, the half hour training exercise failed to identify the SUV despite the fact that the vehicle had a purposely planted “sample” of cesium-137.

However, earlier in the day, 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. The ability to detect even a radiological weapon is impacted by the sensitivity of the detector and the concentration of the material when a sample is taken. Being close to the "subject" and being able to detect the material is not really surprising.

The implication of this material in the context of a “dirty bomb” is that an explosion with cesium-137 would paralyze the Wall St. financial district, not so much with a high casualty rate, but on the infrastructure (the materials could fuse with asphalt and concrete and prevent access to critical urban areas such as buildings, train stations, or tunnels).

With time running short, police operators blamed technical glitches, and the pilot turned back to a West Side landing pad. The test sweep, which followed a secret, concerted search for radioactive materials in Manhattan by hundreds of local, state and federal officers before the city's New Year's Eve celebration, underscores the government's determination to prove this year that it can detect and disrupt nuclear threats to major cities.

Once again it seems to be a question of evaluating the cost benefit relationships of defending against a low threat that might have enormous and catastrophic consequences if the “unlikely event” actually occurred.

This is related to a program begun back in 2006 under the leadership of Vayl Oxford, director of DHS's Domestic Nuclear Detection Office. Called “Securing the Cities,” the program is intended to enhance the protection and response capabilities in and around the Nation’s highest risk urban areas by helping state and local officials to develop urban and regional deployment and operations strategies, identify appropriate detection equipment, establish the necessary support infrastructure, and develop incident management protocols to respond to a small scale “dirty bomb” attack.

However, it should be noted that in some of the references on this program that some officials recognize that it isn’t a perfect program, and that it needs to evolve. While that is true of almost any research program looking into uncharted areas, there has been a considerable amount of money spent on radiation detectors for our ports and transportation depots. But the question of addressing the threat of urban nuclear terrorism

To date, the Securing the Cities program has cost approximately $90 million, with critics raising questions about its value in light of its expansion without any clear and specific threat of urban nuclear terrorism. Additionally, while the “plan” is to use the New York City detection system as a model for other cities, as shown by the fly over episode, the program faces significant technical challenges. Frankly, developing sensors to detect things, even radiological materials, is not a simple task, especially given variable and unpredictable dispersal patterns of weapons components.

Michael Levi, a Council on Foreign Relations scholar and the author of the recently published book "On Nuclear Terrorism," said the Securing the Cities program may be useful but that its backers should be more open about its goals and limits. He also worries that too much is being spent on technology and not enough on coordination.

Thus, while acknowledging that the program is not perfect, supporters like Jonah Czerwinski, an IBM homeland security consultant believe that it will evolve over time (that seems to be a reasonable assumption). Oxford’s position, also reasonable, is that you don’t want to wait for an attack on “a city with a nuclear weapon or dirty bomb and wait to figure that out. Together with the high risk New York always faces, we feel this is a prudent step to help secure that city, as well as to determine, 'Does this model work?' "

In preparation for this unimaginable event, the DHS, NYPD, the Port Authority of New York and New Jersey, and officials from three states and 91 localities have created a partnership in which local officers have been trained in radiation detection operations, and basic, hand-held radiation detectors have been distributed to thousands of police officers and others whose daily work has them crisscrossing the region. Additional funds have been allocated to purchase six half-million dollar trucks equipped with detectors distinguish different radioactive materials

The problems are many. Some experts comment that current detection equipment would have a difficult time finding a lead-shielded improvised nuclear bomb with weapons-grade uranium. This type of a device would emit a much smaller radioactive signal. Additionally, continuing difficulties in communications and data transfer to manage monitoring efforts and in developing new investigative procedures remain challenges.

This is just another chink in our defensive armor. Its not a criticism so much as it is a realization of the difficulties involved in detecting things like a radiological weapon in a densely populated area. None of this even touches on the very real question of air dispersion following an attack using a radiological, chemical or biological weapon. Attempts at modeling the air flow over the canyons in Manhattan have been performed. The actual results of course are classified. But imagine the difficulties in determining the direction in which a plume of just about any airborne toxin or agent, given the always variable wind directions up and down the avenues and the cross streets, and then stirred by the passing traffic or the subterranean rush of air up the Avenue of the Americas as a subways passes beneath.


The Thunder Run has linked to this post in the - Web Reconnaissance for 02/11/2008 A short recon of what’s out there that might draw your attention, updated throughout the day...so check back often.

Just a few comments:

1. The most valuable assertion in this document is Michael Levi's assertion that the lack of collaboration between Federal and local jurisdictions. This is pronounced and gettng worse.

2. Basic education in radiological principals and detection equipment use is a great idea for locals, but several realities must be realized:
a. Locals do not have the time to understand sophisticated analysis techniques, so detector readings are not always what they seem to the novice spectroscopist.
b. Automatic identification algorithms work well in a well-defined spectrum, but could report anamolous results in a noisy or low-signal spectrum. Do not always believe what the read-out says, concentrate on what the data is.
c. Locals should use the expetise resident in the National Labs to help analyze results, but do not always know they are available.

3. As you pointed out in this article, radiation detection is a tricky business. False hope in detector systems and misanalysis could cause more problems than the incident itself, especially if the device is a suspected Radiological Dispersion Device.

4. This is a good basic article and is accurate in its assertions. This is not a common reality in similar articles. Good job.