The Myth of the "Dirty Bomb"

Over the last two years, a lot of attention has been paid by the news media and various government agencies to the potential of a terrorist using a nuclear "dirty bomb" to spread radioactive material over a large area. The thought is that it is unlikely for a terrorist to be able to obtain sufficient quantities of fissile material (enriched uranium, plutonium, etc.) to produce a workable atomic bomb, and so in lieu of setting off a nuclear blast, a terrorist may find it easier to obtain some used Cesium-137 waste (a gamma emitter used to irradiate food and treat cancer) or other radioactive substance to attach to a small bomb, which would, in theory, spread the radioactive material over a large area.

In reality, however, this type of attack is both impractical and unlikely for three main reasons:

• Hard to obtain: Radioactive material such as Cesium-137 is difficult to obtain in sufficient quantities to cause real damage. Since 9/11, the difficulty of obtaining this type of material has grown exponentially.
• Difficult to handle: Cesium-137 is a gamma emitter, which means that the radiation it produces can pass like X-rays through clothing, skin, and even brick walls. Thus, this material requires very skilled handling with specialized equipment to fabricate it into a weapon without injuring or killing its handler.
• Not enough dramatic effect: Terrorists like to create terror through dramatic events: the Oklahama City bombing was a dramatic event, and so was 9/11. The Madrid train bombings, USS Cole bombing, and African embassy bombings were all dramatic and scary. A dirty bomb does none of this - it spreads a small amount of radioactive fallout over an area, which may slightly increase the statistical number of cancer cases and mutations in that area, and may even cause a few local people to get sick from radiation poisoning. But, there is nothing dramatic about it.

A large conventional bomb or a crude chemical weapon is easier to obtain the raw ingredients for, easier to fabricate, and produces a much more dramatic effect than a "dirty bomb". Consider that the bomb that destroyed the Federal Building in Okhahoma City was a simple concoction called "Ammonium Nitrate and Fuel Oil" (ANFO), the ingredients of which were very easy to obtain: ammonium nitrate is a common fertilizer, and the "fuel oil" component is simple kerosene or diesel fuel. As the citizens of Oklahoma City can attest, even a "crude" explosive like ANFO can be very deadly in large quantities like a truck bomb.

Crude chemical weapons are also relatively easy to make and use, and in any enclosed space can be deadly since an enclosed space concentrates the poison and inhibits it from dissipating. The Aum Shinrikyo terrorists in Japan created havoc in the Tokyo subway system by releasing homemade sarin nerve gas. And, a cruder but much simpler poison-gas weapon can be made by mixing together two common ingredients available at your local grocery store.

In short, while a "dirty bomb" may sound interesting on the evening news, it would be much more difficult to build and much less effective than a conventional explosive or chemical weapon. Why would a terrorist want to go through all this effort when the terrorists in Oklahoma City (Timothy McVeigh et al) were able to buy their bomb ingredients at a local farm supply store and a local gas station? If terrorists were actually that stupid, we would not have to worry much about them, but unfortunately, they are not stupid.

Why, then, is the US government so concerned about the possibility of someone using a "dirty bomb"?

I suspect it might be to distract the American public from the relative ease of building a real nuclear bomb.

Coming next week: "The real terrorist nuclear threat"....