Pro-tip to any aspiring carjackers out there: If you're going to steal a truck, make sure it's not one filled with radioactive waste.

On Monday, a driver transporting discarded cobalt-60 from medical devices in Mexico stopped along a highway to take a nap—also a bad idea—when two gunman carjacked his truck.

The thieves likely had no idea of the trucks contents—odds are they targeted it because it's a new-ish (2007) Volkswagen with an attached crane. But the carjacking triggered a minor international panic, and the International Atomic Energy Agency issued a statement about the theft.

"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."

Unfortunately, that's just what the thieves did; last night, authorities discovered the truck, with the shielding removed and the cobalt-60 exposed.

"The person or people who took this out are in very great risk of dying," Mardonio Jimenez, a physicist for Mexico's Commission of Nuclear Safety and Safeguards, told NBC News. The average time of survival after such an exposure is between one and three days, according to Jimenez.

The material was discovered half a mile from a town of about 6,000 people, but authorities say the population isn't at risk.

"Fortunately there are no people where the source of radioactivity is," Juan Eibenschutz, director general of the Commission on Nuclear Safety, said. "What's important is that the material has been located and the place is being watched to guarantee no one gets close."

[Image via AP]