The capsule, which is silver, round and measures just 6 by 8 millimetres in size, was lost sometime between January 10 and January 16 while it was being transported between the mine north of Newman and north-east Perth.
While it cannot be weaponised, WA Health has warned it could cause significant health concerns.
“Exposure to this substance could cause radiation burns or severe illness – if people see the capsule or something that looks similar, stay away from it and keep others away from it too,” Chief Health Officer Dr Andrew Robertson said.
“Do not touch or pick it up. The public is asked to report it immediately by calling 13 DFES (13 33 37).
“If you have touched the material, or have been close to it for an extended period, contact your local health practitioner or visit a hospital emergency department and tell them that you think you may have been exposed to radioactive material.
“If you are very close to the material or touching it, the radiation risk increases immensely and could cause serious damage to your health, including causing radiation burns to the skin.”
The state’s emergency department is conducting a search for the device after it was reported missing to police on January 25 – more than a week after it was actually lost.
“A multi-agency Incident Management Team, comprised of Department of Fire and Emergency Services (DFES), Department of Health, WA Police and other subject matter experts, are confirming the exact route and stops made during the journey from north of Newman,” David Gill from DFES said.
“The start and finish of the transportation journey – the mine site north of Newman and the transport depot in the north-eastern suburbs of Perth – were among the locations searched yesterday and today.
“We are also combing roads and other areas in the search zone.”