Authorities scanning a remote Australian highway for a small radioactive capsule found it on the side of the road after an arduous search they likened it to trying to find a needle in a haystack.
State emergency authorities announced the discovery of a capsule containing highly radioactive Cesium-137 six days after Wednesday afternoon. A package sent hundreds of kilometers from a Rio Tinto mining site in northern Western Australia to the capital Perth was found missing.
“It’s been very difficult to locate this object – search teams have literally found a needle in a haystack,” State Emergency Minister Stephen Dawson said at a press conference on Wednesday.
The capsule’s disappearance prompted a massive highway search by special radiation detection units and the public was warned not to approach the capsule, which could cause serious burns on skin contact.
Authorities believe the capsule, which is about 8 millimeters high and 6 millimeters in circumference, somehow fell into the back of a truck while being transported 1,400 kilometers (870 miles) from the mine along the Great Northern Highway.
Rio Tinto, which uses the rig at its Gudai-Darry iron ore mine, said it regularly transports and stores hazardous cargo as part of its business and employs expert contractors to handle radioactive materials.
In a statement on Wednesday, chief executive Simon Trott said the company was “incredibly grateful” for the work being done to find the capsule and once again apologized to the community for its loss.
“While the recovery of the capsule is an excellent testament to the skill and perseverance of the search team, the fact is that it should never have been lost,” he said. “We are taking this incident very seriously and are fully and thoroughly investigating how it happened.”
Officials said the missing capsule was discovered at 11:13 a.m. local time Wednesday by crews using radiation detection equipment, about two meters from the road, south of the small town of Newman.
Authorities said a 20-meter containment zone had been set up around the capsule and it would be moved to a lead container before being taken to a security facility in Newman.
On Thursday, he will begin his journey south again – this time to the health department in Perth.
Andrew Robertson, Chief Health Officer and Chair of the Radiological Board, said no one appeared to have been exposed to radiation while the capsule was missing.
“It didn’t move – it looks like it went off the track and onto the side of the road. It’s so remote that it’s not in any major communities, so it’s unlikely that anyone would be exposed to the capsule,” he said.
The WA Department of Emergency Services (DFES) on Friday warned residents of a radioactive leak across the state, including in the north-eastern suburbs of Perth, home to about 2 million people.
The capsule was placed inside a package on January 10 and removed by a contractor from Rio Tinto’s Gudai-Darry mine on January 12, officials said.
The vehicle spent four days en route and arrived in Perth on January 16, but was only unloaded for inspection on January 25 – when it was discovered the capsule was missing.
The incident came as a shock to experts who said radioactive materials such as Cesium-137 are highly regulated with strict protocols for handling, storage and disposal.
Radiation ServicesWA says radioactive materials are transported across Western Australia every day without any problems. “In this case, there was a failure of control measures that are normally implemented,” he said, adding that it had nothing to do with the loss of the capsule.
DFES Commissioner Darren Klemm said the capsule was found in “the best possible area” due to its remote location and it was “amazing” to find it so soon.
“There’s been a lot of work done around the subway before based on some intelligence … so you can’t imagine there’s an element of surprise for the people in the car when the equipment jams,” he said.
Cesium-137 can cause serious health problems for people who come into contact with it: burns from close exposure, radiation sickness and potentially fatal cancer risks, especially for those unknowingly exposed for long periods of time.
Robertson, the chief health officer, said standing within a meter of the capsule for an hour would be equivalent to receiving a radiation dose of 10 X-rays.
Officials feared the capsule could get caught in the tires of another vehicle and be carried away from the search zone. It could also have been taken from the area by an animal – or worse, taken and kept by someone unaware of the dangers.
The risk wasn’t just short-term—Cesium-137 has a half-life of about 30 years, meaning the capsule’s radioactivity would have halved after three decades, and halved again after 60 years, meaning the lost capsule could have remained radioactive for up to 300 years.
Robertson said it was unlikely that the capsule would have contaminated the surrounding soil as it sat unattended for days on the side of the highway.
“It’s covered in stainless steel, so it’s unlikely there’s any contamination in the area unless the actual source itself is seriously damaged after falling off the back of a truck.”
Robertson is investigating the disappearance of the capsule and will present a report to the health minister in the coming weeks.
Emergency Services Minister Dawson said the recovery of the capsule was an “extraordinary result”.
“I think West Australians can sleep better tonight,” he said.
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