Authorities have found it on the side of the road for a small radioactive capsule that went missing on a remote Australian highway after a search as challenging as trying to find a needle in a haystack.
State emergency officials announced the discovery Wednesday afternoon, six days after the capsule containing highly radioactive cesium-137. A package sent hundreds of kilometers from a Rio Tinto mining site in northwest Australia to the capital Perth was discovered missing.
“Finding this object has been a huge challenge – search teams have found exactly the needle in the haystack,” the state’s emergency services minister, Stephen Dawson, told a news conference on Wednesday.
The capsule’s disappearance triggered a massive search of the highway with specialized radiation detection units – and a warning to the public not to approach the capsule, which could cause serious burns if it comes in contact with the skin.
Authorities believe the capsule – about 8 millimeters high and 6 millimeters across – somehow fell off the back of a truck while it was being transported 1,400 kilometers (870 miles) along the Great Northern Highway from the mine.
Rio Tinto, which used the device in gauge at its Gudai-Darri iron ore mine, said it regularly transports and stores hazardous goods as part of its business and hires specialist contractors to handle radioactive materials.
In a statement on Wednesday, chief executive Simon Trott said the company was “incredibly grateful” for the work done to find the capsule and once again apologized to the community for its loss.
“The recovery of the capsule is a great testament to the skill and tenacity of the expedition team, and the point is that it should never have been lost in the first place,” he said. “We take this incident very seriously and will conduct a full and thorough investigation into how it happened.”
Authorities said crews using radiation detectors discovered the missing capsule two meters from the road south of the small town of Newman at 11:13 a.m. local time on Wednesday.
Officials said a 20-metre exclusion zone had been set up around the capsule and it would be transferred to a lead container before being taken to a secure location in Newman.
On Thursday it will begin traveling south again – this time to the Department of Health facility in Perth.
Andrew Robertson, chief health officer and chairman of the Radiation Council, said it did not appear that anyone had been exposed to radiation from the capsule during the time it was missing.
“It doesn’t look like it’s moved – it looks like it fell off the track and onto the side of the road. It is so remote that it is not in any major community so it is unlikely that anyone was exposed to the capsule,” he said.
The WA Department of Emergency Services (DFES) issued an alert on Friday warning residents of a radioactive leak in the state, including the north-east suburb of Perth, home to about 2 million people.
According to authorities, the capsule was placed in a package on January 10 and collected from Rio Tinto’s Gudai-Dari mine site by a contractor on January 12.
The vehicle spent four days on the road and arrived in Perth on January 16, but was unloaded for inspection on January 25 – when it was discovered the capsule was missing.
The incident shocked experts who said the handling of radioactive materials such as cesium-137 is strictly regulated with strict protocols for its transport, storage and disposal.
Radioactive Services WA says it transports radioactive materials throughout Western Australia daily without any problems. “In this case, there appears to be a failure of the control measures normally implemented,” it said in a statement, 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” because of its remote location and it was “amazing” that it had been found in such a short time.
“There was a lot of work going on around the metro area based on some intelligence initially… So, you can’t imagine that there would be an element that could surprise the people in the car when the equipment goes up,” he said.
Cesium-137 can cause serious health problems for people who come into contact with it: burns from close exposure, radiation sickness and deadly cancer risks, especially for those who are unknowingly exposed for long periods of time.
Chief Health Officer Robertson said standing one meter from the capsule for an hour was equivalent to receiving a radiation dose of 10 X-rays.
Officials fear that the capsule may have been lodged in the tires of another vehicle and transported far away from the search area. It could also have been carried out of the area by an animal – or worse, picked up and kept by someone unaware of the dangers.
The risk isn’t just in the short term – cesium-137 has a half-life of about 30 years, meaning the capsule’s radioactivity will halve after three decades and halve again after 60 years. The capsule can remain radioactive for as long as 300 years.
Robertson said the capsule sat unattended for days next to the highway, contaminating the surrounding soil.
“It’s covered in stainless steel, so it’s unlikely that there’s going to be any contamination in the area, unless it causes significant damage to the actual source, which is unlikely to happen from falling off the back of a truck.”
Robertson is investigating the capsule’s disappearance and will 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 Western Australians can sleep better tonight,” he added.