Emergency crews are on the hunt for a pea-sized radioactive capsule along a 870-mile/1,400-kilometre route in Western Australia after the tiny device went missing while being transported from Rio Tinto's Gudai-Darri mine in the Kimberley region.

According to a BBC report, the capsule – just 6mm in diameter and 8mm long, contains Caesium-137, which can cause serious illness to anyone who comes into contact with it, including burns, skin damage or radiation sickness.

Authorities fear the piece, which is part of a density gauge in use at the remote operation but which was being transported elsewhere by a contractor company, could have been found by someone and kept as a souvenir or picked up by a vehicle tire during the lengthy route.

BBC noted that it left the mine site on 12 January and an inspection of the broken gauge was performed on 25 January, so the component could now have been missing more than two weeks. Experts told the news service vibrations during its transport could have caused the bolts to loosen and the device to fall through its casing.

Special equipment for detecting radiation has been deployed to look for the small component, with technology reportedly attached to patrol vehicles that will scan the route in both directions over a five-day period.

“As part of this investigation, we are working closely with the contractor to better understand what went wrong in this instance,” Simon Trott, chief executive of Rio Tinto's iron ore division, told the BBC.

"Prior to the device leaving the site, a Geiger counter [a device to detect radioactivity] was used to confirm the presence of the capsule inside the package," he said, noting that state officials have issued a radiation alert warning of the potential danger.

Search crews told the news outlet that they have a “pretty good” change of locating the small device.

Source: BBC