Since the mid 1990s, amateur smugglers have been caught trying to sell nuclear material from the former Soviet Union. Very little of the material was suitable for a nuclear bomb. The smugglers sometimes transported the radioactive material without shielding, leaving some of them with a bad case of radiation sickness. But with the recent fear of "dirty bombs" (explosives used to spread radioactive material), this black market in radioactive material has become more of an issue. Three months ago, Russian police caught a man smuggling 20 pounds of radioactive thorium powder out of Kazakhstan. For the last few years, Chechens have been offering to buy radioactive material (but haven't done anything with it yet.) There are tons of radioactive material (for medical or industrial use) being used around the world. And on any given day, a lot of it is being moved to and from the places where it is used or made. Some New York City police cruise around with radiation detectors, although all they have caught so far are legitimate couriers taking radioactive material to legitimate users. This stuff is normally moved about in unmarked cares or vans and is rarely given an armed guard. Anyone with inside information on the shipments of radioactive material could arrange to steal it. This may be preferable to trying to bring it into the United States from overseas, as an increasing number of radiation detectors are being used at ports and airports.