Radioactive capsule no bigger than a coin lost amid sands of western Australia

A coin-sized silver capsule containing a radioactive element has disappeared in western Australia. 

The radioactive element cesium, which is used in mining gauges, cannot be weaponized but can make people sick. It was lost in transit between a Rio Tinto mine in Newman and Perth, a drive equivalent to one between the District of Columbia and Orlando, Florida.

On Jan. 10, the capsule was packaged for repair and left the mine on Jan. 12, then reached Perth on Jan. 16. The package that was supposed to contain the cesium capsule was opened Wednesday.

“Upon opening the package, it was found that the gauge was broken apart with one of the four mounting bolts missing and the source itself and all screws on the gauge also missing,” an alert from the Western Australia Department of Fire and Emergency Services reads.

Crews searched the mine, transport depot and roads used to transport the substance Thursday and Friday, turning up nothing. Officials are warning the public that if they see the capsule, stay away and alert authorities.

“Exposure to this substance could cause radiation burns or severe illness. If people see the capsule or something that looks similar, stay away from it and keep others away from it too. Do not touch or pick it up,” Western Australia Department of Health Chief Andrew Robinson said.

In an hour, the capsule can emit 2 millisieverts, akin to 10 X-rays.

Authorities believe that vibration from driving caused the capsule to fall out of its loosened case. Theft was ruled out, as antitampering tape was found on the box when it was opened Wednesday.

“We believe the vibration of the truck may have impacted the integrity of the gauge, that it fell apart and the source actually came out of it,” Mr. Robertson told the Associated Press. 

Rio Tinto has started its own investigation.

“Rio Tinto engaged a third-party contractor, with appropriate expertise and certification, to safely package the device in preparation for transport off-site ahead of receipt at their facility in Perth. Prior to the device leaving the site, a Geiger counter was used to confirm the presence of the capsule inside the package,” the mining company said.