Authorities scanning an isolated Australian highway for a tiny missing radioactive capsule found it by the side of the road, after a difficult search comparable to searching for a needle in a haystack.
State emergency authorities announced the discovery Wednesday afternoon, six days after the capsule, containing highly radioactive cesium-137, was found missing in a package sent hundreds of miles from a Rio Tinto mine site in northern Western Australia to the capital Perth.
“Localizing this object was a monumental challenge – search groups literally found the needle in the haystack,” state Emergency Services Minister Stephen Dawson told a conference. press on Wednesday.
The capsule’s disappearance sparked a massive search of the highway with specialized radiation detection units – and prompted the public to warn the public not to approach the capsule, which could cause severe burns to the skin contact.
Authorities believe the capsule – about 8 millimeters high and 6 millimeters round – somehow fell out of the back of a truck as it was being transported 1,400 kilometers ( 870 miles) along the Great Northern Highway from the mine.
Rio Tinto, which used the device in a gauge at its Gudai-Darri iron ore mine, said it regularly transports and stores dangerous goods as part of its business and hires expert contractors to handle radioactive materials. .
In a statement Wednesday, chief executive Simon Trott said the company was “incredibly grateful” for the work undertaken to find the capsule and again apologized to the community for its loss.
“While the capsule’s recovery is a great testament to the skill and tenacity of the search team, the fact is that it should never have been lost in the first place,” he said. . “We take this incident very seriously and are conducting a full and thorough investigation into how it happened.”
Authorities said the missing capsule was detected at 11:13 a.m. local time on Wednesday, two meters off the road just south of the small town of Newman by teams using radiation detection equipment.
Officials said a 20-meter exclusion zone had been set up around the capsule and it would be transferred to a lead container before being taken to a security facility in Newman.
On Thursday, he would resume his journey south – this time to a Perth Health Department facility.
Chief Health Officer and Chairman of the Radiological Council Andrew Robertson said it does not appear anyone was exposed to radiation from the capsule during the time it was missing.
“It doesn’t appear to have moved – it appears to have fallen off the runway and landed on the side of the road. It’s far enough away that it’s not in any large community so it’s unlikely anyone was exposed to the pod “, did he declare.
The Department of Emergency Services WA (DFES) sounded the alarm on Friday, alerting residents to the presence of a radioactive spill in the state, particularly in the north-eastern suburbs of Perth, which is home to around 2 million people.
According to authorities, the capsule was placed in packaging on January 10 and recovered from Rio Tinto’s Gudai-Darri 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 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 the handling of radioactive materials like cesium-137 is highly regulated with strict protocols for its transport, storage and disposal.
Radiation Services WA says radioactive material is transported daily throughout Western Australia without any problems. “In this case, there appears to be a failure of control measures generally implemented,” he 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” due to its remote location and finding it in such a short time was “incredible”.
“A lot of work was done around the metro area based on some early intelligence…so you can’t help but imagine there was an element of surprise for the people in the car when the equipment has gone up,” he said.
Cesium-137 can create serious health problems for people who come into contact with it: burns from close exposure, radiation sickness and life-threatening cancer risks, especially for people unknowingly exposed for long periods of time. periods.
Robertson, the health official, said standing one meter from the capsule for an hour would be equivalent to receiving the radiation dose of 10 x-rays.
Officials feared the capsule had become lodged in the tires of another vehicle and transported away from the search area. It could also have been taken from the area by an animal – or worse, picked up and kept by someone unaware of the dangers.
And the risk was not only short-term – cesium-137 has a half-life of about 30 years, which means that after three decades the capsule’s radioactivity would halve, and after 60 years it would again halve, meaning that the radioactivity lost capsule could have remained radioactive for up to 300 years.
Robertson said the capsule was unlikely to have contaminated surrounding soil because it lay unattended for days near the highway.
“It’s encased in stainless steel so it’s unlikely unless there has been significant damage to the source itself, which is unlikely from a fall of the back of a truck, there will be contamination in the area.”
Robertson is investigating the disappearance of the capsule and will submit a report to the Minister of Health in the coming weeks.
Dawson, the emergency services minister, said the capsule’s recovery was an “extraordinary achievement”.
“I think West Australians can sleep better tonight,” he added.