MEXICO CITY — The theft of a truck carrying radioactive material, the kind used in hospitals but also potentially as a dirty bomb, unnerved Mexico and set off a two-day hunt before both the vehicle and its potentially lethal contents were found Wednesday at nightfall.
The truck had been transporting the material, cobalt 60, from an obsolete radiotherapy machine at a public hospital in Tijuana to a storage repository in central Mexico. It was in a sealed container on the bed of the truck when armed men hijacked it at a gas station on Monday.
It was unclear if the thieves were after the truck, a 2007 Volkswagen Worker, or the cobalt, which is extremely dangerous and can kill a person exposed to it directly in a matter of minutes. The theft prompted the International Atomic Energy Agency, the nuclear monitor of the United Nations, to issue an alert expressing concern about its whereabouts.
Mardonio Jiménez, a top-ranking official with Mexico’s nuclear safety commission, said the thieves had opened the box holding the sealed container and appeared to have carried it several hundred meters from the truck and opened it.
He said the motive was unclear, but whoever handled the material, which was recovered, would likely end up in a hospital, “and we will be waiting for them.” A wide area of Hueypoxtla, a small town 40 miles north of Mexico City where the truck was found, has been cordoned off but Mr. Jiménez said there was no immediate public health threat.
The episode raised concerns about securing discarded nuclear material. It was unclear what if any security precautions had been taken in transporting the material, but truck hijackings are common in Mexico — both of vehicles and cargo — and terrorists are known to be interested in cobalt 60.
An American military official said that while the Pentagon was monitoring the Mexico situation closely, the theft did not appear to be connected to terrorist activity.
Still, the material is one of the ingredients commonly cited as a possible component of a dirty bomb, a combination of explosives and radioactive material.
Counterterrorism officials have said such weapons are far more useful in spreading panic than harming people. Just scattering a radioactive isotope in a densely populated area would have the same effect, but the person delivering the isotope would probably receive a large dose.
After the Sept. 11, 2001, attacks, the United States went on a campaign to ensure that cobalt 60 and other isotopes commonly used in medicine and industry were better protected against theft.
In an online guide to radiation protection, the E.P.A. identifies cobalt 60 as a substance used in a range of industrial and medical applications, including radiotherapy in hospitals. Large amounts of cobalt 60 are also used to sterilize spices and some foods because its powerful gamma rays kill bacteria and other pathogens without damaging the products or leaving them radioactive.
The E.P.A. guide also warns that cobalt 60 is known to cause cancer.
Industrial and medical users periodically replace used cobalt 60 with fresh supplies because, as with all radioactive isotopes, its emissions slowly weaken over time; its half-life is 5.27 years.
The authorities in Mexico said the truck departed Tijuana on Nov. 28 en route to a repository 30 miles northeast of Mexico City. When it stopped at a gas station, two armed men ordered the driver out of the truck, tied him up and made off with the truck.
Many trucks in Mexico carry warnings that they are tracked by satellite, though it was unclear if that was the case with this stolen truck. Experts also say thieves have become adept at disabling the systems.
It was not the first time a dangerous cargo like cobalt 60 had been seized by outlaws in Mexico or raised public health alarms. In the 1980s, discarded cobalt 60 in Ciudad Juárez near the United States border was found to have been used in making reinforcing rods for construction, causing an international health scare.
Randal C. Archibold reported from Mexico City, and Rick Gladstone from New York. Matthew L. Wald and Eric Schmitt contributed reporting from Washington, and Patrick J. Lyons from New York.
The truck had been transporting the material, cobalt 60, from an obsolete radiotherapy machine at a public hospital in Tijuana to a storage repository in central Mexico. It was in a sealed container on the bed of the truck when armed men hijacked it at a gas station on Monday.
It was unclear if the thieves were after the truck, a 2007 Volkswagen Worker, or the cobalt, which is extremely dangerous and can kill a person exposed to it directly in a matter of minutes. The theft prompted the International Atomic Energy Agency, the nuclear monitor of the United Nations, to issue an alert expressing concern about its whereabouts.
Mardonio Jiménez, a top-ranking official with Mexico’s nuclear safety commission, said the thieves had opened the box holding the sealed container and appeared to have carried it several hundred meters from the truck and opened it.
He said the motive was unclear, but whoever handled the material, which was recovered, would likely end up in a hospital, “and we will be waiting for them.” A wide area of Hueypoxtla, a small town 40 miles north of Mexico City where the truck was found, has been cordoned off but Mr. Jiménez said there was no immediate public health threat.
The episode raised concerns about securing discarded nuclear material. It was unclear what if any security precautions had been taken in transporting the material, but truck hijackings are common in Mexico — both of vehicles and cargo — and terrorists are known to be interested in cobalt 60.
An American military official said that while the Pentagon was monitoring the Mexico situation closely, the theft did not appear to be connected to terrorist activity.
Still, the material is one of the ingredients commonly cited as a possible component of a dirty bomb, a combination of explosives and radioactive material.
Counterterrorism officials have said such weapons are far more useful in spreading panic than harming people. Just scattering a radioactive isotope in a densely populated area would have the same effect, but the person delivering the isotope would probably receive a large dose.
After the Sept. 11, 2001, attacks, the United States went on a campaign to ensure that cobalt 60 and other isotopes commonly used in medicine and industry were better protected against theft.
In an online guide to radiation protection, the E.P.A. identifies cobalt 60 as a substance used in a range of industrial and medical applications, including radiotherapy in hospitals. Large amounts of cobalt 60 are also used to sterilize spices and some foods because its powerful gamma rays kill bacteria and other pathogens without damaging the products or leaving them radioactive.
The E.P.A. guide also warns that cobalt 60 is known to cause cancer.
Industrial and medical users periodically replace used cobalt 60 with fresh supplies because, as with all radioactive isotopes, its emissions slowly weaken over time; its half-life is 5.27 years.
The authorities in Mexico said the truck departed Tijuana on Nov. 28 en route to a repository 30 miles northeast of Mexico City. When it stopped at a gas station, two armed men ordered the driver out of the truck, tied him up and made off with the truck.
Many trucks in Mexico carry warnings that they are tracked by satellite, though it was unclear if that was the case with this stolen truck. Experts also say thieves have become adept at disabling the systems.
It was not the first time a dangerous cargo like cobalt 60 had been seized by outlaws in Mexico or raised public health alarms. In the 1980s, discarded cobalt 60 in Ciudad Juárez near the United States border was found to have been used in making reinforcing rods for construction, causing an international health scare.
Randal C. Archibold reported from Mexico City, and Rick Gladstone from New York. Matthew L. Wald and Eric Schmitt contributed reporting from Washington, and Patrick J. Lyons from New York.