This photo was handed out by Mexico's Interior Ministry showing a box for carrying radioactive material. (via Getty Images)

MEXICO CITY -- It's like a glitch in the Internet, a skipping needle on the vinyl of world news.

The same strange and very specific crime story keeps repeating itself in Mexico: Car thieves steal a load of dangerous radioactive material without knowing what they've taken, setting off a brief public health scare and a scramble to find the goods. For at least the third time in the past year and a half, Mexican authorities late Wednesday were warning that pilfered hazmats were on the loose.

An alert has gone out to five Mexican states after a container of Iridium 192 used in industrial x-rays was stolen from a truck in the southeastern state of Tabasco. If removed from its container, the material could cause burns or other injuries and "is very dangerous to people," Mexico's civil protection agency said in a statement. Extended exposure for hours or days could be fatal.

The theft occurred Monday night in the parking lot of a Soriana -- a Wal-Mart-like retail and grocery store -- in the town of Cardenas, said Alejandro Cortes Carmona, the deputy director of Mexico's nuclear safety commission.

The truck drivers had left their vehicle, which was marked with hazmat signs and warnings, and when they returned the Iridium container was gone, Cortes said.

"I want to be clear that the motive was not to steal the radioactive material," he said. "It was simply to take everything that they found in the vehicle. And they took the radioactive material in its container without knowing what was inside."

Authorities were investigating whether the company that owned the material, Garantia Radiografica e Ingenieria, had followed protocols in handling it. Asked why the truck was parked unattended at a Soriana at night, Cortes said, "We don't know."

The most serious recent radioactive caper took place in December 2013, when unwitting car thieves pilfered a load of Cobalt-60 as it was being moved from a hospital in Tijuana to a storage facility in central Mexico. The robbery caused a brief dirty-bomb scare, but the thieves soon ditched the Volkswagen cargo truck. Six people were arrested, but worries they might die from exposure proved unfounded.

Mexican officials say they now plan to revise their regulations on the transport of radioactive materials to try to prevent future thefts, Cortes said.

In each recent case, he said, "the thieves never knew what they were stealing, and when they figured it out, they abandoned the material." He added, "Fortunately, we've not had any deaths."

Gabriela Martinez contributed to this report.

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