Mexican authorities are investigating the theft of a pickup truck that was transporting potentially dangerous radioactive material, the country’s interior ministry said Sunday.

Officials were notified of the vehicle’s theft on Saturday, according to a news release.

The ministry said the truck was transporting a container of iridium-192, a radioactive material used in industrial radiography. Officials say the material does not pose a threat to anyone if it remains in its container, but it “represents a major health risk” if it were to be removed.

According to the Centers for Disease Control and Prevention (CDC), iridium-192 gives off strong gamma radiation, and exposure can be deadly. It could also cause burns or radiation sickness.

In its news release, Mexico’s interior ministry said anyone who does not handle the material properly could experience “permanent or serious injury” in a matter of minutes or hours.

It encouraged anyone who locates the material to stay at least 30 meters away from it.

The theft was reported by an industrial maintenance center in San Juan del Rio, according to the ministry, a city about 130 miles northwest of Mexico City in the country’s Queretaro district.

Authorities in Queretaro and five other nearby districts have been notified of its disappearance.

This is at least the fourth time that radioactive material has been stolen in Mexico in the past four years, according to past news releases. The material was found in all three prior cases.

In April 2015, the ministry announced that a container of iridium-192 was stolen out of a pickup truck in Cadenas. The container was located nine days later, unopened, on a pedestrian bridge.

The previous July, Mexico’s interior ministry announced that it had located stolen radioactive material in Tlalnepantla de Baz, and the recovered material did not pose a danger to the public.

The International Atomic Energy Agency announced in early December 2013 that a pickup truck carrying cobalt-60 was stolen near Mexico City, though the undamaged material was found two days later in a field close to where the theft occurred.