Radioactive capsule lost in Australia… Small but lethal

Australia is shaken by the disappearance of a radioactive capsule. The capsule, which carries the risk of death should people reach out and touch it with their bare hands, is actually quite small at 8mm by 6mm in length.

The Rio Tinto mining company, which owns the capsule, apologized Monday for the disappearance and said the state government supports the search for the capsule, which contains cesium-137, a highly radioactive substance used in mining equipment.

Authorities believe the capsule, which emits gamma and beta rays, fell from the back of the truck on the 1,400-kilometre stretch of the Great Northern Highway. Due to the small size of the capsule and the large area where it was lost, authorities say the capsule is unlikely to be found. They also state that while it may have traveled farther from the search area, it could pose a radioactive health risk to anyone who encounters the capsule for the next 300 years.

HOW WAS IT LOST?

State authorities have sounded the alarm warning residents of the presence of a radioactive spill in the southern part of the state, including the north-eastern suburbs of the capital Perth, where some 2 million people live.

The capsule was placed in a package on January 10 and picked up by a carrier on January 12 at Rio Tinto’s Gudai-Darri mine. The vehicle arrived in Perth on January 16, after four days. The disappearance of the capsule was discovered on January 25.

“When we opened the package, we found that all the gauge screws with the solder were missing,” the Department of Fire and Emergency Services (DFES) said.

The pack is believed to have been damaged by bumpy roads and the mounting bolt holding the pack in place has come off.

HOW DANGEROUS?

Experts warn that it can cause serious health problems if it comes in contact with Cesium-137. Nearby exposure carries risks of skin burns, radiation sickness, and potentially fatal cancer, especially for those with unknowing prolonged exposure.

Radiation Services WA says that staying within a meter of the capsule for an hour will emit about 1.6 millisieverts (mSv), which is roughly equivalent to the radiation received from taking 17 standard chest X-rays.

In a company statement, it was stated that taking the capsule with bare hands could cause serious damage to fingers and surrounding tissues.

Ivan Kempson, Associate Professor of Biophysics at the University of South Australia, said the worst-case scenario would be a curious child picking up the capsule and putting it in his pocket: “This is rare, but it can and has happened before. . There are some previous examples of people finding similar things and getting radiation poisoning, but they were much stronger than the current missing pod. We are all constantly exposed to radiation from things around us and from the food we eat, but the main concern right now is the potential health impact on the person who finds the capsule.”

THE EXPERTS ARE SHOCKED

The experts, who said the transport, storage and destruction of radioactive materials such as cesium-137 are strictly regulated by strict protocols, said they were shocked by the situation.

Rio Tinto stated that they regularly transport hazardous materials as part of their work. In the statement, the small capsule was claimed to be part of a hydrometer used at the Gudai-Darri mining site.

Pradip Deb, a professor and radiation safety officer at RMIT University in Melbourne, says safety rules require the capsule to be transported in highly protective cases, but loss is highly unusual.

SEARCH WORKS

The authorities try to find the capsule with vehicles traveling at 50 kilometers per hour in both directions of the road and equipped with special radiation detection equipment. “It will take around five days to navigate the original route,” DFES said in a statement.

Dale Bailey, professor of medical imaging science at the University of Sydney, says the search has to be slow: “Radiation detectors in moving vehicles can be used to detect radiation above natural levels, but the relatively low amount of radiation at the source means that the area will have to be scanned relatively slowly.”

Authorities are warning the public not to come within five meters of the device, while stating that they are aware of the difficulty of seeing such a small capsule and treating it accordingly.

Health Director Dr. Andrew Robertson warned people to stay away from the radioactive capsule if they found it.

The search for the capsule is not going very well. Authorities are concerned that the capsule is no longer within the search area and that it got stuck in the tire of another vehicle and was transported a greater distance.

Nuclear policy analyst and environmental expert Dave Sweeney said: “Imagine, for example, that a raptor is taking the capsule out of the search area, there is too much uncertainty and it will cause more problems.” This resource definitely needs to be found and secured, but there are too many variables and we don’t know what it might be.”

WHAT HAPPENS IF IT IS NOT FOUND?

The half-life of cesium-137 is about 30 years, so after thirty years the radioactivity in the capsule will be halved. At this rate, RMIT University said the capsule could be radioactive for the next 300 years: “Cesium-137 is a normally closed source; that is, if it does not break, it does not contaminate the soil or the environment, nor does it transfer radioactivity”.

Rio Tinto, one of the world’s largest mining giants, operates 17 iron ore mines in the Pilbara region of Western Australia. The company’s mining operations have caused controversy in the past, including the demolition of two ancient rock shelters in Juukan Strait in 2020, prompting then-CEO Jean-Sébastien Jacques to resign after apologizing.