A device containing Iridium-192 has been reported stolen from Iran’s Bushehr nuclear power plant, could be used to construct a dirty bomb.

A device containing the nuclear material Iridium-192 has gone missing from Iran’s Bushehr Nuclear Power Plant and may have been stolen, according to a report by the Saudi newspaper Asharq Al-Aawsaat.

It is feared that the material could be used to construct a dirty bomb, a conventional weapon equipped with nuclear material which is used to spread nuclear material and deadly radiation around the area of the explosion.

Asharq Al-Aawsaat reported that a vehicle carrying the device was stolen as it was being transported from the Bushehr facility. The vehicle was later found, but the device was gone.

The identity of the thief is unknown, as is the reason the purpose for which the device was stolen.

The International Atomic Energy Agency (IAEA defines) Iridium-192, a highly unstable isotope which emits both electrons and gamma-rays, as a category-2 radioactive substance. It is used primarily to locate structural flaws in metals. Substances with a category-2 classification can permanently injure or even kill a human being if exposed to the material within hours or days.

The theft was reported to the IAEA earlier this month. The IAEA then warned neighboring Gulf States of the danger the isotope poses.