A major mining company Rio Tinto, has apologised for losing a tiny radioactive capsule that was being transported across Western Australia.
Along the 1,400 km (870 mile) route, there is an urgent search for the object, which is about the size of a pea.
A tiny amount of radioactive Caesium-137 is present in the capsule, and anyone who comes into contact with it runs the risk of developing serious illness.
This might involve burns, radiation sickness, or skin damage.
Radiation detectors and other specialised equipment are being used by emergency services to find the device.
But Australia’s Department for Fire and Emergency Services said the silver capsule – which is just 6mm (0.24 inches) in diameter and 8mm long – was so small it might have become lodged in the tyre of a vehicle passing along the road.
The capsule may have gone missing up to two weeks ago.
Rio Tinto, which has big mining operations in Australia and has been the subject of a series of controversies in recent years, said it was sorry for the alarm that had been caused.
The firm would be launching its own investigation into what had happened, it said in a statement.
The lost device is part of a density gauge, common in the mining industry. It was being used at Rio Tinto’s Gudai-Darri mine in the remote Kimberley region.
The gauge was being transported by a subcontracted company, who picked it up from the mine site on 12 January to move it to a storage facility in the north-east suburbs of Perth.
When it was unpacked for inspection on 25 January the gauge was found broken apart and the radioactive capsule was gone. One of four mounting bolts and screws were also missing.
The authorities said vibrations during transit may have caused the bolts to become loose, allowing the capsule to fall through gaps in the casing and truck.
Analysis, Phil Mercer, Sydney
The search route is huge. It is roughly equivalent to the distance by road from John O’Groats in Scotland to Land’s End in Cornwall, or from Washington DC to Orlando, Florida.
Specialist radiation detection equipment is being fitted to patrol vehicles that will cover the length of it. Over five days, they will travel in both directions along the Great Northern Highway at speeds of around 50km/h (30mph).
Emergency authorities in Western Australia say the chances of finding the tiny device are “pretty good”. But if it has become lodged in another vehicle’s tyre it could be well outside of the search zone already.
Or if it is found by a member of the public, they might inadvertently keep it as a souvenir.
So the authorities are keen to stress that holding the capsule could result in radiation burns, while long-term exposure could cause cancer.
“As part of this investigation we are working closely with the contractor to better understand what went wrong in this instance,” said Simon Trott, chief executive of Rio Tinto’s iron ore division.
“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 [a device to detect radioactivity] was used to confirm the presence of the capsule inside the package,” said Mr Trott.
State officials have issued a radiation alert across a vast swathe of Western Australia as the search for the capsule continues.
Exposure to trace quantities of the metal is like “receiving 10 X-rays in an hour, just to put it in context, and… the amount of natural radiation we would receive in a year, just by walking around,” said Western Australia’s chief health officer Andrew Robertson.
The state’s desert is remote and one of the least populated places in the country. Only one in five of Western Australia’s population lives outside of Perth, the state’s capital.
However, officials say they are concerned that someone could pick up the capsule, not knowing what it is.
“If you have contact or have it close to you, you could either end up with skin damage, including skin burns… and if you have it long enough near you, it could cause what is called acute radiation sickness, and that will take a period of time,” Mr Robertson added.
This incident comes as Rio Tinto tries to repair its reputation in Australia after it was hit by a backlash for destroying sacred Aboriginal rock shelters in Western Australia.
In 2020, Rio Tinto blasted the 46,000-year-old rock shelters at Juukan Gorge to expand an iron ore mine, sparking a major outcry that led to several of the company’s top bosses standing down.
And last year, a parliamentary inquiry found sexual harassment was rife at Australia’s mining firms, after an internal review at Rio Tinto found more than 20 women had reported actual or attempted rape or sexual assault over five years.