“We are taking this incident very seriously,” Rio Tinto head of iron ore Simon Trott said in a statement on Sunday. “We recognize this is clearly very concerning and are sorry for the alarm it has caused in the Western Australian community.”

The mining giant and Western Australia’s government are attempting to find the widget, which is as much as 8 millimeters (0.3 inch) in length and contains a small amount of the radioactive isotope caesium-137. While the risk to the general community is low, exposure to the substance could cause radiation burns or radiation sickness, Emergency WA said on its website.

The widget was a component in a gauge used to measure the density of iron ore. Rio said the radioactive capsule was collected from the mine on Jan. 12 by a transport contractor, and was due to arrive at a radiation storage facility in Perth on Jan. 16. It was only discovered to be missing when its container was opened for inspection on Jan. 25. 

The Western Australian government said when the package holding the device was inspected, it was found to have been “broken apart with one of the four mounting bolts missing and the source itself and all screws on the gauge also missing.” 

It comes as Rio Tinto, which is listed in Sydney and London, attempts to rebuild its reputation after destroying a site of sacred significance to Indigenous Australians in 2020 as part of an iron ore mine expansion.