The International Atomic Energy Agency said Thursday after stolen radioactive medical material was recovered in central Mexico that the general public was not in danger.
"Based on the information available, the Mexican authorities and the IAEA believe the general public is safe and will remain safe," the U.N.'s nuclear agency said in a press release.
Although the radioactive material contained in the teletherapy device had been removed from its protective shielding, apparently by the thieves, the agency said there was no indication it had been "damaged or broken up" and no sign of contamination in the area.
It added that it remained in "close contact" with Mexican authorities and said the actions they had taken in response to the discovery of the source were "appropriate" and in keeping with the agency's guidelines.
The radioactive cobalt-60 source, which went missing earlier this week when a truck transporting it was stolen, has an activity of 3,000 curies (111 terabequerels) and is considered Category 1, meaning it is "extremely dangerous" to people, the IAEA said.
"If not safely managed or securely protected, it would be likely to cause permanent injury to a person who handled it or who was otherwise in contact with it for more than a few minutes," the U.N. agency said.
"It would probably be fatal to be close to this amount of unshielded radioactive material for a period in the range of a few minutes to an hour."
Since the truck and radioactive material were located Wednesday afternoon near the town of Hueypoxtla, Mexico state, not far from where the vehicle was stolen, Mexican authorities have been assessing potential radiation exposure to persons who may have been near the unshielded source.
Hospitals also have been alerted to watch for patients with symptoms of such exposure.
People exposed to source, however, do not pose a contamination risk to others, the IAEA said.
The truck was stolen on Monday in Tepojaco, a town north of Mexico City, while transporting the cobalt-60 from a hospital in the northern border city of Tijuana to a radioactive waste storage center. EFE