After a tiny, dangerously radioactive capsule was lost in the Western Australian desert in mid-January, the authorities feared that it could take weeks or even months to find it. The device was smaller than a penny, while the search zone was an 870-mile stretch of highway cutting across vast tracts of desert.
But the search took just six days, with the authorities announcing on Wednesday afternoon that the capsule had been recovered in what they called an “extraordinary result.”
“The search crews have literally found the needle in the haystack,” Stephen Dawson, the emergency services minister for Western Australia state, said at a news conference.
The authorities had launched the large-scale search, involving the defense force, emergency services and radiation experts, after the capsule was discovered to be missing last week.
A small silver cylinder measuring 0.3 inches by 0.2 inches, the device contains a small amount of cesium-137 that makes it dangerously radioactive, officials said. An hour of exposure to it from a meter away is the equivalent of receiving 10 X-rays, and prolonged exposure can burn the skin, and, in severe cases, cause acute radiation sickness, they said.
The capsule, which is part of a sensor used in mining, was lost sometime between Jan. 12 and Jan. 16 while being transported from a Rio Tinto mine site near Newman, in the remote north of Western Australia, to the state’s capital, Perth. But the box that it was transported in was not opened for another 11 days, at which point the sensor was found in pieces and the capsule was missing, the authorities said.
They believe that vibrations from the truck ride caused the sensor to shake apart and also dislodged a mounting bolt, leaving a hole in the bottom of the box. The capsule is believed to have fallen out of the sensor, through the bolt-hole, onto the surface of the truck and bounced onto the road.
The capsule was discovered on Wednesday morning, after a vehicle equipped with radiation detection equipment picked up a signal not far from the location of the start of the truck’s journey, according to Mr. Dawson.
A search team was then deployed to the area and soon found the capsule, about 6.5 feet from the side of the road, he said.
Darren Klemm, Western Australia’s fire chief, said that the authorities had been discussing worst-case scenarios, “working through the possibility that we wouldn’t find it.”
“That’s the basis of the discussions we were having: At what point do you stop looking for it?” he added. “The worst possible outcome was we were still going to be here in 12 months’ time looking for something on, in some places, really remote stretches of road.”
A 65-foot containment zone has been set up around the capsule, said Mr. Dawson, the minister, adding that it would subsequently be placed into a lead box and transported to Perth.
The capsule was found in a remote location with no nearby communities, and nobody appears to have been injured by it, said Dr. Andrew Robertson, the state’s chief health officer.
He added that the authorities will now investigate how the capsule was lost, including how the sensor was handled and transported.
In a statement, Rio Tinto’s chief executive, Simon Trott, said that the company was launching its own “full and thorough investigation” of how the capsule was lost, including considering if it was appropriate to hire a special contractor to package radioactive material, as had happened in this case.
“I’d like to apologize to the wider community of Western Australia for the concern it has generated,” he added.
Under state law, the maximum penalty for failing to safely store, pack and transport radioactive materials is only a $707 (1,000 Australian dollars) fine, a figure that was criticized by the Australian prime minister, Anthony Albanese, earlier on Wednesday.
“That figure is ridiculously low,” Mr. Albanese said at a news conference. “But I suspect that it is ridiculously low because people didn’t think that such an item would be lost.”