Updated Jan 30, 2023 - Energy & Environment

Authorities search for tiny radioactive capsule missing in Australia

Trucks travel along an access road at the Gudai-Darri iron ore mine operated by the Rio Tinto Group in the Pilbara region of Western Australia, Australia, on Tuesday, June 21, 2022.

Trucks travel along an access road at the Gudai-Darri iron ore mine, operated by the Rio Tinto Group, in the Pilbara region of Western Australia in June 2022. Photo: Carla Gottgens/Bloomberg via Getty Images

Mining giant Rio Tinto apologized Monday as authorities in Western Australia searched for a tiny radioactive capsule that went missing in the vast Australian state.

Driving the news: A radiation alert was issued across parts of W.A. after the capsule containing a small amount of radioactive Caesium-137 vanished while being transported from Rio Tinto's Gudai-Darri mine in the remote Pilbara region to a storage facility about 870 miles away in state capital Perth, authorities said.

Context: W.A. is Australia’s largest state, with a total land area of some 975,685 square miles.

  • It is sparsely populated and 75% of its 2.7 million residents live in Perth.

The big picture: A specialist contractor picked the silver capsule that's 0.24 inches wide and 0.31 inches long up from the mine that's near Newman on Jan. 12 and it was transported by truck to the storage facility on Jan. 16, the Department of Fire and Emergency Services (DFES) in Western Australia said.

  • It was discovered to be missing on Jan. 25 when the gauge was unpacked for inspection. Emergency services were notified and a search began soon after. Authorities announced two days later that the capsule had vanished.
  • "Upon opening the package, it was found that the gauge was broken apart with one of the four mounting bolts missing and the source itself and all screws on the gauge also missing," per a statement from the Department of Fire and Emergency Services (DFES) in Western Australia.
An image of the capsule next to an Australian 10 cent coin, which is larger than it, to give an idea of how tiny it is.
An image of the capsule next to an Australian 10-cent coin. Photo: Department of Fire and Emergency Services, Western Australia.

State of play: "DFES and radiation specialists are searching along Great Northern Highway by driving north and south directions at slow speeds," said DFES in an update Monday, urging people to take care when approaching and use caution when overtaking the search party.

  • "Exposure to this substance could cause radiation burns or radiation sickness. ... Risk to the general community is relatively low, however, it is important to be aware of the risks," the statement added.

What they're saying: "We are taking this incident very seriously. We recognize this is clearly very concerning and are sorry for the alarm it has caused in the Western Australian community," said Rio Tinto's iron ore division chief Simon Trott in a statement to media Monday.

  • "As well as fully supporting the relevant authorities, we have launched our own investigation to understand how the capsule was lost in transit," Trott added.
An image showing parts of Western Australia affected by a radiation warning, from Newman in the Pilbara region to state capital Perth,  due to a missing radioactive capsule.
Photo: Department of Fire and Emergency Services, Western Australia/Facebook

Of note: Western Australia's Chief Health Officer Andrew Robertson said at a news conference Saturday that W.A. authorities decided to hold off until Friday to publicly announce that the capsule had gone missing while authorities searched the mine and storage facilities and confirmed the transportation route.

  • Investigators concluded the capsule hadn't been stolen after finding the box it was stored in contained "anti-tampering" tape and police determined that the matter was an accident, per Australian Associated Press.

What we're watching: "There is the potential that we may not find this," given the extensive distance the truck traveled, said DFES Chief Superintendent Country North David Gill at Saturday's news conference.

Editor's note: This article has been updated with additional details throughout.

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