Sometime between 10 and 16 January 2023, aradioactive capsule containingcaesium-137 was lost from a truck inWestern Australia. The capsule was being transported 1,400 kilometres (870 mi) fromRio Tinto's Gudai-Darriiron ore mine nearNewman to a depot in thePerth suburb ofMalaga. TheDepartment of Fire and Emergency Services announced to the public on 27 January that the capsule had gone missing, and that the capsule was potentially deadly and could causeburns andradiation sickness. It was discovered on the side of the road near Newman on 1 February.
The capsule is 6 mm × 8 mm (0.24 in × 0.31 in) in size,[1] and is used as part of anucleonic level sensor in the crushing circuit[2] iniron ore mining. The capsule contains 19gigabecquerel[3] ofcaesium-137 as a ceramic source.[4][5] The amount of radiation emitted by the capsule could induce burns and radiation sickness and is potentially deadly to humans.[1]
On 10 January 2023, the capsule was packed in order for repair works to be carried out in Perth.[6]
Between 11 and 14 January, the capsule left Rio Tinto's Gudai-Darri mine[6] for transport. The package that was supposed to contain the capsule arrived in Perth on 16 January and was unloaded and placed into secure storage. The package was unpacked for inspection on 25 January; the inspection found that one of four mounting bolts and all screws on the gauge were missing, and the capsule itself was also missing. Authorities surmised that the bolt had worked loose because of vibrations during the 1,400-kilometre (870 mi) journey, and then the capsule had fallen through the bolt hole.[7]
On the evening of 25 January, theDepartment of Fire and Emergency Services (DFES) was notified of the missing capsule by theWestern Australia Police Force.[8]
TheChief Health Officer of Western Australia,Andrew Robertson, held an emergency press conference, with DFES issuing an "urgent public health warning" on 27 January.[8][7] Members of the public were warned to observe a safe distance of 5 metres (16 ft) if they found the capsule, and drivers who had recently used theGreat Northern Highway were asked to check their vehicle tyres in case it was lodged in the tread.[7]
A search was carried out after the capsule was reported missing, with more than 100 personnel involved. The DFES Agency flew out scientists from the eastern states to operate a Geiger Counter.[9] Agencies assisting the search included theAustralian Radiation Protection and Nuclear Safety Agency, WA Police, DFES, and theAustralian Nuclear Science and Technology Organisation.[10]
The capsule was found next to a road on 1 February, 74 kilometres (46 mi) south of Newman by a search crew vehicle travelling past it at 70 kilometres per hour (43 mph). The presence was noticed when the detection equipment picked up radiation emitted by the capsule.[9][1] Authorities said it was unlikely it caused harm to anyone in the time it was lost.[11]
Prime MinisterAnthony Albanese has criticised the low penalty for losing radioactive materials in Western Australia. Under the Radiation Safety Regulations Act, the maximum penalty for failing to safely store, pack and transport radioactive materials is aA$1,000 fine. TheGovernment of Western Australia has stated it will review the penalties for mishandling radioactive materials, but any change will not be retroactive.[12][13] In July 2023, it was confirmed Rio Tinto would not be fined as "no breaches of the radiation safety act had been identified" when the "tiny, but potentially deadly" capsule was lost, although "issues stemming from the investigation [...] to provide input into updates of national safety standards" continue to be considered.[14]
Rio Tinto offered to pay for the search costs.[15] After discussion with Western Australia government, Rio donated a mobile camp worth $4 million to assist in flood recovery ofFitzroy Crossing, in lieu of cash payment.[16]
The search and subsequent recovery of the capsule has been likened to finding a "needle in a haystack" by the media and authorities.[17][18]
'The inquiry did not identify any breaches of the Radiation Safety Act by Rio Tinto or its licensees or employees and no adverse findings against Rio Tinto or its licensees have been recorded.' Without any finding of wrongdoing, it's understood no penalty will be imposed against [... Rio Tinto].
