Mexican authorities successfully completed the extremely dangerous task of returning a highly radioactive material into a safe container where it belongs.

Specialists from Mexico’s National Nuclear Security Commission used a remote-controlled robot to perform the task. Last week, thieves hijacked the truck carrying Cobalt-60, a radioactive substance used for medical and industrial applications. Cobalt-60 can also be used to make explosives. Police located the truck, but found the robbers removed the cobalt from its protective case, exposing themselves to dangerous levels of radiation, before dumping it less than a mile away.

The six men suspected of stealing the dangerous cargo have been treated for signs of radiation exposure and remain under police guard.