Decades after an atomic bomb exploded on remote islands off Western Australia's coast, ex-serviceman Jim Marlow can still picture what he saw from 10 kilometres away.
"It frightens the s**t out of you because you couldn't say you expected it because you didn't, you didn't know it was coming," he said.
"A loud bang followed by a rumble … and you see the smoke [and] sand starting to build up and it goes up and up and up and lines the sky."
Radiation is still present on the Montebello Islands, 70 years after the British military conducted Australia's first-ever nuclear weapons test, and it is not clear if the islands are completely safe.
Since 2019, an Edith Cowan University study has been measuring how much radioactivity still exists in the marine sediment on the islands.
The team has collected and tested more than 100 samples of marine sediment and marine life from the archipelago of islands.
Lead researcher and PhD student Madison Williams-Hoffman said researchers were still investigating the full extent of the radiation, and the risks it posed.
"Most of it follows our original hypothesis, but we also have some unexpected areas with slightly higher levels," she said.
"The next bit is once we know [the radioactivity map] and we've collected a few organisms and analysed them … then we can calculate up to a potential person or dose risk," she said.
The scenic archipelago is among the world's most biodiverse marine environments and a popular spot for tourists and fishers to visit.
Ms Williams-Hoffman said it was unrealistic to put a blanket ban on visitation to the area, as the islands' remote location made it difficult to police.
She hoped the study's findings would give people the power to make an informed decision as to whether they were comfortable visiting the area.
"Even if you tell someone you can't go there because [of] radiation risks, there's always someone who'll want to and you won't entirely be able to stop them," she said.
"But to give them the information so that they can make the decision for themselves, I think it's a really important output from this project."
Ms Williams-Hoffman said the study's first findings will be published next year.
Memories of blast remain
Jim Marlow, one of many Australian servicemen who witnessed the test, watched the historic moment from the deck of a small ship.
"We knew something was happening but there was little detail about it. We were just told to assemble on the deck, we were told to cover our heads and our eyes," Mr Marlow said.
It was a shocking sight.
Mr Marlow, who is also part of the Australian Ex-Serviceman Atomic Survivors Association, has spent years lobbying for atomic veterans to receive recognition.
He previously told the ABC he was worried his exposure to radiation all those years ago could still pose a threat to his health.
"In the case of the atomic veterans, the fallout from the detonation stays with you for a lifetime, so you don't leave your war zone, it follows you everywhere you go," he said.
"Fifty years later it's still after you. I don't know when it's going to come and get me. I don't know when it's going to come to get my grandkids."
