Radioactive capsule missing in Australia after falling off mining truck

An urgent search is under way to find a tiny but potentially deadly radioactive capsule that has gone missing in Australia.

The 8mm by 6mm unit, smaller than a penny, is believed to have fallen off the back of a truck while being transported 870 miles from a mine to a depot in the city of Perth.

The unit was lost after a screw became loose inside a large lead-lined gauge and it fell through a hole. The small silver cylinder contains caesium-137, a highly radioactive isotope which experts say cannot be weaponised.

The unit emits the equivalent of 10 X-rays in an hour and members of the public should stay at least 16ft away from it, state authorities said. Contact could result in skin damage, burns and radiation sickness, including effects on the immune system. Long-term exposure could also cause cancer.

It went missing on a 22-mile stretch of road as it was being transported from the Rio Tinto mine in Newman to the Perth suburb of Malaga.

The Department of Fire and Emergency Services has deployed teams with handheld radiation detection devices and metal detectors to try to find it, but state authorities have been hampered by a lack of equipment and have called for external assistance.

Search teams are concentrating their efforts on populated areas north of Perth and sites along the Great Northern Highway.

Superintendent Darryl Ray said: "What we're not doing is trying to find a tiny little device by eyesight.

"We're using the radiation detectors to locate the gamma rays," he said.

Authorities are using the truck's GPS data to determine the exact route the driver took and where it stopped during its journey. They are concerned the capsule could have lodged in another vehicle's tyre and could be hundreds of miles away from the search area.

Rio Tinto had contracted an expert radioactive materials handler to package the capsule and transport it "safely" to the depot, and was not told it was missing until 25 January.

Read more on Sky News:
Mining giant Rio Tinto reveals second largest payout in FTSE 100 history
'Disturbing' findings of rape and bullying in workplace review at mining giant Rio Tinto
Rio Tinto CEO steps down over destruction of 46,000-year-old Aboriginal caves

The Western Australia government waited two days to inform the public on Friday. Its chief health officer Andrew Robertson defended the delay, saying the mine and depot had to be searched and excluded, and the route confirmed.

"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," he said. "It is unusual for a gauge to come apart like this one has."

"Our concern is someone will pick it up, not knowing what it is, think this is something interesting (and) keep it."

Police have determined the incident to be an accident and no criminal charges are likely as they have ruled out theft at the depot.