A radiation warning is in place for parts of Western Australia after a tiny capsule containing cesium-137 was lost.
Mining giant Rio Tinto has apologized as the search continues for a small radioactive capsule that went missing while being taken to a warehouse in Perth, sparking a radiation scare in parts of Western Australia.
The silver-colored capsule, just 6 mm (0.24 in) wide and 8 mm (0.31 in) long, was lost while being transported from Rio Tinto’s Gudai-Darri mine near Newman, in the remote Kimberley region, to a warehouse of about 1400 km (870 miles) away in Perth.
It is unclear how long the tiny capsule, which contains cesium-137, a radioactive isotope that emits radiation equal to 10 X-rays per hour, has been missing.
The capsule left the site on January 12, and a contractor hired by Rio Tinto notified the company that it was missing on January 25. The public was alerted two days later.
Rio Tinto said it was taking the disappearance very seriously.
“We understand that this is obviously very concerning and we regret the alarm it has caused in the Western Australian community,” Simon Trott, head of iron ore at Rio Tinta, said in a statement on Monday.
“Rio Tinto engaged a third-party contractor, with the appropriate expertise and certification, to securely package the device in preparation for off-site transport prior to receipt at their Perth facility,” he said, adding that Rio was also conducting its own investigation into how the loss occurred.
Before the device left the site, a Geiger counter was used to confirm the presence of the capsule inside the package, Rio Tinto said. Authorities believe the device fell from the truck while it was being moved.
“We have completed radiological surveys of all areas where the device was and inspected the roads within the mine as well as the access road leading from the Gudai-Darri mine,” Trott said.
Authorities have advised people to keep at least five meters (16 feet) away, and a radiation warning remains in place in parts of the vast country.
Health officials warned that the capsule could cause burns or nausea if handled.
“The concern is that someone will pick it up not knowing what they’re dealing with,” said Dr Andrew Robertson, Western Australia’s chief health officer.
The capsule is packed in accordance with transport and radiation safety regulations inside a box attached to a pallet, he added.
“We believe that the vibration of the truck may have affected the integrity of the meter, that it disintegrated and the source actually came out of it,” Robertson said. “It’s unusual for a gauge to disintegrate like this.”
The state Department of Fire and Emergency Services deployed teams with hand-held radiation detection devices and metal detectors along the 36 km (22 mile) busy freight route to search for the container.
“What we’re not doing is trying to find the tiny device by sight,” Superintendent Darryl Ray said, adding that they were concentrating on populated areas north of Perth and strategic locations along the Great Northern Road.
“We use radiation detectors to locate gamma rays,” he said.
Authorities are also using the truck’s GPS data to determine the exact route the driver took and where he stopped after leaving the mine. It arrived at the warehouse in Perth on January 16.
There are concerns that it could have become stuck in the tires of a vehicle traveling on the same road.