By Holly Yan and Christine Theodorou
A truck carrying a dangerous radioactive substance used in medical treatment has been stolen in Mexico, the International Atomic Energy Agency said Wednesday.
Mexican authorities told the IAEA that the truck, which was transporting the cobalt-60 teletherapy source from a hospital in Tijuana to a radioactive waste storage center, was stolen Monday in Tepojaco, near Mexico City.
"At the time the truck was stolen, the source was properly shielded," the IAEA said. "However, the source could be extremely dangerous to a person if removed from the shielding, or if it was damaged."
The U.S. Department of Homeland Security is assisting with the investigation into the stolen truck, Mexican authorities said.
Mexico alerted the IAEA to the theft, following international protocol for such incidents, said Jaime Aguirre Gomez, deputy director of radiological security at the National Commission for Nuclear Security and Safeguards.
The radioactive material had been used in radiotherapy for cancer treatments at a Tijuana hospital and was no longer in use, he said.
The shielding that protects the cobalt-60 is designed so that the radioactive source is difficult to extract, Aguirre said. The casing is designed not to be opened or perforated easily.
Cobalt-60 can be used for medical and industrial purposes, he said.
CNN's Carloo Perez and Evan Perez contributed to this report.
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