Editor’s Note, February 6, 2023: The capsule was found and safely recovered on February 1. Search crews driving some 125 miles from the mine site detected gamma radiation, which led them to the capsule about 6.5 feet from the side of the road. Officials said it is unlikely anyone was exposed and that the capsule would be transported to a health facility in Perth.
Authorities in Western Australia are searching for a tiny, radioactive capsule believed to have been lost in transit earlier this month. On Tuesday, the country’s nuclear safety agency joined the effort to find the substance, which poses a public health threat.
The radioactive silver cylinder is smaller than a dime—just six millimeters in diameter and eight millimeters tall—but exposure to it could cause burns and radiation sickness. And it’s missing somewhere along a stretch of desert roughly the length of California’s coastline.
Between January 12 and 16, a truck carrying a package with the capsule inside traveled 870 miles from a mine near the small town of Newman to a depot northeast of Perth. It was unpacked for inspection on January 25, at which point it was discovered that the capsule was missing, per Western Australia’s Department of Fire and Emergency Services (DFES). Officials alerted the public to the potential danger on January 27.
Authorities believe vibrations during the drive dislodged a bolt from the container, and the capsule fell out through the bolt hole, writes Cason Ho of the Australian Broadcasting Corporation. From there, it is thought to have bounced off the surface of the truck into the road.
The capsule contains a radioactive isotope of cesium called cesium-137. “It does emit a reasonable amount of radiation,” Andrew Robertson, Western Australia’s chief health officer, said during a news conference on Friday, per Vice’s Matthew Gault. If a person stood one meter away from the substance for an hour, they would be exposed to the equivalent of receiving ten X-rays, or the amount of radiation a person normally receives in a year.
Long-term exposure to the capsule could cause cancer, per BBC News’ Monica Miller, Lucy Hooker and Phil Mercer.
“If people see the capsule or something that looks similar, stay away from it and keep others away from it too,” Robertson says in a statement.
“From what I have read, if you drive past it, the risk is equivalent to an X-ray,” Andrew Stuchbery, a nuclear physicist at the Australian National University, tells Reuters’ Melanie Burton. “But if you stand next to it or you handle it, it could be very dangerous.”
Authorities are now sweeping the 870-mile stretch of road over which the capsule could have been lost, per the Associated Press (AP). The DFES is using radiation survey meters to try to detect radiation from the capsule and locate it.
“What we are not doing is trying to find a tiny little device by eyesight,” Darryl Ray, acting superintendent for DFES, said at a news conference on Saturday, according to the New York Times’ Yan Zhuang. “We are using the radiation detectors to locate the gamma rays, using the meters, that will help us then locate the small device.”
Stuchbery tells Reuters that it is “not impossible” that the searchers will find the capsule. “If the source just happened to be lying in the middle of the road you might get lucky … it’s quite radioactive, so if you get close to it, it will stick out,” he says to the publication.
Robertson tells NBC News’ Mithil Aggarwal that radioactive material is regularly transported around Western Australia under strict regulations. “It is extremely rare for a source to be lost,” he tells the publication.
Police determined the loss of the capsule was an accident, per the AP. Rio Tinto, the corporation that mined the radioactive substance, apologized for the incident in a statement and said they have launched their own investigation into how the capsule was lost. It was being transported by a third-party contractor.