Hueypoxtla, Mexico — Mexican authorities on Wednesday recovered a truck and the radioactive medical equipment it was hauling to a waste facility when gunmen stole it from a gas station two days before.

The radioactive material, cobalt-60, was found about a half-mile from the truck and its empty protective lead container near Mexico City, said Juan Eibenschutz, director general of the National Commission of Nuclear Safety and Safeguards.

"The highly radioactive material had been removed from its container and anyone involved in opening the box could be in grave danger of dying within days. Fortunately there are no people where the material was left and the radioactivity is," Eibenschutz said.

Eibenschutz said the truck was found in Hueypoxtla, an agricultural town of about 4,000 people. The cargo truck hauling the extremely dangerous radioactive cobalt-60 from used medical equipment was stolen from a gas station early Tuesday, and authorities had put out an alert in six central states and the capital looking for it.

The truck was carrying a metal container of cobalt-60 to a nuclear waste facility in the state of Mexico, which is adjacent to Mexico City.

Eibenschutz said direct exposure to the cobalt would result in death within minutes.

"This is a radioactive source that is very strong," Eibenschutz told press, adding that it can be almost immediately fatal, depending on proximity.

Eibenschutz didn’t know the exact weight, but said it was the largest amount stolen in recent memory, and the intensity of the material caused the alert. Local, state, and federal authorities, including the military, joined the search for the truck.

The material was used in obsolete radiation therapy equipment that is being replaced throughout Mexico’s public health system. It was coming from the general hospital in the northern border city of Tijuana, Eibenshutz said.

Before the container was found, he said the thieves most likely wanted the white 2007 Volkswagen cargo vehicle with a moveable platform and crane.

Eibenschutz said there was nothing so far to indicate the theft of the cobalt was intentional or in any way intended for an act of terrorism.

The truck marked "Transportes Ortiz" left Tijuana on November 28th and was headed to the storage facility when the driver stopped to rest at a gas station in Tepojaco, in Hidalgo state north of Mexico City. The truck has a GPS locator but it wasn't active at the time of the theft.

The driver, Valentin Escamilla Ortiz, told authorities he was sleeping in the truck when two men with a gun approached about 1:30 am Tuesday. They made him get out, tied his hands and feet, and left him in a vacant lot nearby.

When he was able to free himself, he ran back to the gas station to get help.

On average, a half dozen thefts of radioactive materials are reported in Mexico each year and none have proven to be aimed at the cargo, Eibenschutz said. He said that in all the cases the thieves were after shipping containers or the vehicles.

Unintentional thefts of radioactive materials are not uncommon, said an official familiar with cases reported by the International Atomic Energy Agency. In some cases, radioactive sources have ended up being sold as scrap, causing serious harm to people who unknowingly come into contact with it.

The official, who was not authorized to comment on this latest case, recalled an incident in Mexico in the 1970s when one thief died and the other was injured after they opened a container holding radioactive material. The container was junked and sold to a foundry, where it contaminated some steel reinforcement bars made there. Eibenschutz said all foundries in Mexico now have equipment to detect radioactive material.