Thanks for all the wishes, everyone! Yes, a celebration is a part of it but yes, I do think it's a day just like any other day – perhaps a better one than the average. ;-)Today, 1/3 of the TRF visitors are Hungarians who came from this Hungarian server, index.hu, to my 2011 page about the radioactive source found in Prague's playground which was medically related.
The reason for the new Hungarian report – and many others in the whole world (e.g. Time) – is that some thieves stole a truck in Mexico. Stealing is wrong and these thieves are likely to learn it in the hard way because they're likely to perish because the truck had lots (40 grams) of cobalt-60 in it.
Cobalt-60 is artificially produced from the only stable isotope of this \(Z=27\) element in Nature, cobalt-59 (almost 100% of the naturally occurring cobalt), by neutron activation (absorption of a neutron combined with an excitation of the nucleus). Its half-life is 5.2714 years which is very, very fast (but still long enough to "wait" for your death). The isotope beta-decays to nickel-60 which has \(Z=28\).
It is being used to trace cobalt in chemical reactions; sterilize medical equipment; medical radiotherapy, and so on.
Some of the cobalt-60 that gets into your body is excreted by excrements. Some of it gets to tissues – especially liver, kidneys, and bones – where the radiation eventually causes cancer unless it mostly gets out of your body in time (via urine).
The Czech nuclear watchdog agency has a coherent story with some details.
On December 2nd, the International Atomic Energy Agency was informed by Mexican nuclear watchdogs that a truck (or just its cargo? It doesn't really matter) was stolen when it was bringing the nuclear stuff used for radiotherapy from a hospital in Tijuana (pretty much at the U.S. border, near San Diego) to a nuclear dumping ground in Maquixco (central or Southern Mexico). The stuff was used for radiotherapy and its activity was 111 TBq (3 000 Ci: 100 trillion decays per second just from 40 grams of the substance that was there). Police and other enforcement forces immediately began to look for the thieves to save them; the public was informed about the serious incident.
Two days later, on December 4th, in the afternoon local time, the radioactive source was found extracted from the shielding near the Hueypoxtla town (central or Southern Mexico). A 500-meter no-entry zone was enforced around the source and a safe liquidation is being prepared. Everyone who could have interacted with the source was urged to visit a physician.
Several minutes in the vicinity of such an unshielded source may be enough for death. You could conjecture that the thieves' bodies shouldn't be further than a mile but that's wrong because the death may still arrive after a delay.
Radiotherapy based on cobalt-60 is used all over the world. The EU and Czechia define strict conditions how to deal with this lethal stuff. In Mexico, they're probably less strict. The material wasn't guided by anyone when the truck stopped at a gas station. The driver actually didn't need to refuel; he just wanted to sleep. But he was assaulted by a pair of unlucky thieves.
Of course, in principle, it's conceivable that the thieves knew very well what they were dealing with and how to deal with that. But I find this James Bond scenario a bit unlikely. It seems more likely to me (especially in Mexico) that they didn't know what gift they conquered until they were feeling sick – and then they may have tried to run away but it's probably too late. The expected lifetime in such a situation is just "at most a few days". If they were manipulating with the stuff with their hands, amputation is a necessary but not sufficient condition for survival.
Cobalt-60 irradiation unit used in Czechia.
The security breach is a serious matter – especially because in many poorer countries, they may be as careless as those in Mexico if not more so – because the effects summarized above should assure you that stolen cobalt-60 is an "excellent" material to produce dirty bombs, to kill some people instantly, or to make a place unlivable for generations.
This particular material was probably collected in its entirety but one should be aware of this time bomb.