Mexican authorities said Wednesday afternoon they have recovered a stolen truck that contained the "extremely dangerous" radioactive material, cobalt-60, which is used in medical treatment. The container holding the material was found empty. But Mexican officials have located the cobalt, and they say there is so far no risk to the surrounding population.
Mardonio Jimenez, a National Nuclear Safety Commission official, said that the person or persons who opened the container, however, likely received a lethal dose of radiation.
Authorities are checking local clinics for people who might have fallen ill after coming into contact with the deadly cargo, Jimenez said.
The stolen vehicle, a white Volkswagen Worker truck, was transporting a "teletherapy source" containing the cobalt from a hospital in the northern city of Tijuana to a radioactive waste storage center when it was stolen in Tepojaco near Mexico City on Monday, the International Atomic Energy Agency (IAEA) said. The U.N. atomic watchdog first announced that the vehicle was missing 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," an IAEA statement said.
The IAEA said it was informed about the theft by Mexico's National Commission for Nuclear Safety and Safeguards (CNSNS). It said the truck was stolen at a service station.
Experts have long warned about the risks posed by the large amounts of radioactive material held in hospitals, university campuses and factories, often with little or no security measures to prevent them being stolen.
Such material is highly dangerous to human health if not properly handled. Such material could also, in theory, be used in a so-called "dirty bomb" — an explosive device spreading the radioactive material over a wide area.
Last year alone, the IAEA recorded 17 cases of illegal possession and attempts to sell nuclear materials and 24 incidents of theft or loss. It says this is the "tip of the iceberg."
Many cases have involved former parts of the Soviet Union, such as Chechnya, Georgia and Moldova — where in 2011 several people were arrested trying to sell weapons-grade uranium. But the problem is not confined to Eastern European states
In an incident showing how dangerous such materials are, in Goiania, Brazil in 1987 a machine containing a substance similar to cobalt-60, caesium-137, was left lying around after a cancer unit of a hospital moved.
Thinking it might have scrap value, two people dismantled the equipment and when the radioactive material started glowing blue in the dark it was shown off around the local community as a curiosity.
Eighty-five houses were contaminated and 249 people needed medical treatment. Twenty-eight people suffered radiation burns and four died including a 6-year-old girl who handled the substance while eating.
Major international efforts have been made since the end of the Cold War in 1991 and the Sept. 11, 2001 attacks in the United States to prevent nuclear material falling into the wrong hands.
A report issued in July by the Arms Control Association and the Partnership for Global Security said progress had been made reducing the threat but that "significant" work remained.
Al Jazeera correspondent Adam Raney contributed to this report, with wire services.