A dirty bomb is not a good way to kill lots of people, but it is a great way to scare the hell out of a population. There are reports that Saddam Hussein investigated the possibility of making an RDD in the 1980s and gave up on the idea because it simply wasn’t deadly enough. On the other hand, people are scared of radiation – even in the absence of a genuine radiological threat a dirty bomb attack can still cause deaths from panic, anxiety, and even traffic accidents as people flee the scene (or the city) unnecessarily. I would suspect that by now most terrorist groups understand the relative lack of medical risk to people. I would also suspect they know full well that they also know that, in spite of the relative lack of medical risk, a dirty bomb attack would be tremendously disruptive and that it would cause an enormous economic impact to whatever city was affected. So this means that we’ve got to be serious about controlling radioactive materials – and we’ve got to take seriously reports of radioactive materials trafficking. Even if the radioactivity itself poses little or no risk to the public, we still have to remember that any dirty bomb attack will likely have a significant impact.
This makes recent reports of radioactive materials smuggling a bit troubling.
A few weeks ago, for example, there was a report that the Armenians had broken up a strontium-90 deal. Strontium-90 is one of the nuclides thought more likely to show up in a dirty bomb – there is a ton of it in the world (it is made as a product of nuclear fission) and there are some very high-activity sources in the nations of the former Soviet Union. To give you an idea of the potential risk from Sr-90, consider that 1 curie (1 Ci) can cause skin burns if you hold it in your hand for even a few minutes. Now superimpose on that the fact that, in 1999, some woodsmen in the nation of Georgia found a single source that contained 40,000 curies of this nuclide – it had once been used to power a Soviet-era meteorological station – and there are still sources of this activity (and higher) that are not yet accounted for. The fact that two Armenians were busted trying to sell Sr-90 is not necessarily alarming in and of itself – that would depend on how much they were trying to sell – but it is worth noting.
Also worth noting is that at about the same time the Turks arrested someone trying to smuggle a small quantity of Cs-137 from Georgia. Cesium-137 is another of the nuclides we’re particularly concerned about as a potential dirty bomb component. Like Sr-90, Cs-137 is produced in large quantities in nuclear reactors and, also like Sr-90, there are a large number of high-activity Cs-137 sources in the world. In fact, there’s very likely more Cs-137 in the world than Sr-90. Cs-137 sources have killed people around the world – something that can certainly happen here as well if we let down our guard.
The bright side of these events is that at least we are seeing the nuclides that we consider most likely to be used against us. It would concern me, for example, if the nuclides that were found kept surprising us. Law enforcement agencies should be finding these nuclides for exactly the reasons that they are considered likely to be used in a terrorist attack – they are common, they are frequently used in settings in which radioactive materials security is not necessarily a high priority, and they are often present in high-activity levels. There’s more than that – these nuclides also have a fairly long half-life (which keeps them from decaying to stability too quickly), they both have a fairly high specific activity (so they can pack a lot of activity into a relatively small package), and more. But, again, it is somewhat gratifying that our logic seems to be holding up – that the most commonly smuggled nuclides are pretty much exactly what we’d anticipated.
On the negative side, the fact is that we continue to see a continuing low background level of radiological smuggling – in spite of the fact that such sources are unlikely to cause massive casualties, criminals and terrorists retain their interest in striking with these weapons. This means that not only need to maintain our vigilance to keep intercepting these materials before they can be used maliciously, but we also must maintain our efforts to secure them. The Department of Energy, through its Global Threat Reduction Initiative (GTRI) has done an enormous amount of work to help safeguard sources in the US and overseas – their work has already secured millions of curies of radioactive materials, not to mention thousands of bombs’ worth of highly enriched uranium. When you consider that a single RDD might cause tens or hundreds of billions of dollars of damage and clean-up costs (not to mention the societal and long-term economic impact), the millions of dollars spent to secure these sources certainly seems to be money well-spent. One can hope that their work will be permitted to continue, rather than being subjected to the typical vagaries of the political process.