MEXICO CITY — Police are scouring central Mexico for highly radioactive material stolen this week on the outskirts of the crowded capital.
Unidentified armed men stole a truck transporting the load of cobalt-60, stored in a safe container the size of a car battery, at a highway truck stop shortly after midnight on Monday.
“Evidently they were after the truck,” Mardonio Jimenez, a senior official with Mexico’s National Commission for Nuclear Safety and Safeguards, said of the armed thieves. “So far we haven’t had any success in the search for them. Of course, it’s a worrisome situation.”
The Mexican nuclear agency reported the theft to the United Nations’ International Atomic Energy Agency in Vienna, which issued an alert Wednesday.
“At the time the truck was stolen, the source was properly shielded. However, the source could be extremely dangerous to a person if removed from the shielding, or if it was damaged,” the IAEA said in a statement.
The cobalt, which Jimenez described as “highly radioactive,” was encased in a machine used for cancer radiation therapy. A private trucking company was transferring it from a government hospital in Tijuana, on the California border, to a disposal facility for radioactive material near Mexico City.
GlobalPost explainer: What is cobalt-60?
The driver was catching a nap when he and an assistant were assaulted, the authorities said.
Though potentially lethal to those directly exposed to it for even a few minutes, the cobalt first would have to be removed from its protective casing, Jimenez said, a process he described as “difficult.”
“The risk exists, but we see it as very low,” Jimenez told GlobalPost.
Still, the theft comes three decades after cobalt-60 sold as scrap by clueless cancer clinic workers in the border city of Ciudad Juarez contaminated thousands of tons of steel used for construction in northern Mexico and the southern United States.
That December 1983 incident was discovered months later when sensors detected some of the radioactive steel being used in construction at the US research facility at Los Alamos, New Mexico.
Metal made from the scrapped cobalt later was found in chairs and table legs, and some 17,000 buildings across Mexico, half of which were torn down. More than 15,000 tons of the contaminated steel remains buried at a site in the northern Mexico desert.
Officials have since armed US border crossing stations with sensors to detect radioactive materials.
A similar incident occurred in Brazil in 1987, in which a substance similar to cobalt-60 was collected for scrap from a closed cancer clinic, and handled by unaware residents. More than 80 houses were found to be contaminated by the material, cesium-137, dozens of people suffered radiation burns and four eventually died.
In addition to this week’s search for the stolen truck, Mexican officials have alerted as scrap yards in Mexico City and a half dozen nearby states to be on the lookout for the radiation therapy device or the cobalt’s container.
Cobalt-60 is listed among materials that can be used in constructing a so-called dirty bomb, in which radioactive material can be dispersed through a detonation of conventional explosives.
But experts say while such a bomb is relatively easy to make, it’s not highly lethal.
Although the country suffers criminal violence and a few armed revolutionary cells, Mexican officials say whoever stole the cobalt-armed machinery and truck weren’t after bomb making material.
“We think these were common thieves. The danger is they have no idea what they are dealing with,” Miguel Garcia, assistant secretary of civil protection in Hidalgo, the state where the cobalt was stolen, said in a telephone interview.
“This material is dangerous for anyone directly handling it or nearby. But this isn’t Chernobyl or Fukushima or anything like that,” Garcia said, referring to famous nuclear reactor meltdowns in Ukraine in 1986 and Japan two years ago.
“There isn’t a wider threat,” he said. “This shouldn’t be blown out of proportion.”