Between September 27, 1956, and October 9, 1957, the United Kingdom conducted seven major nuclear tests at Maralinga, a remote site in South Australia. These tests were split into two operations: Operation Buffalo, which included four detonations, and Operation Antler, which included three. Among the tests were One Tree and Breakaway, which had explosive yields of 12.9 and 10.8 kilotons respectively. Some tests were conducted from towers or the ground, while others, like Kite, were dropped from high altitudes by aircraft. Additional nuclear tests were carried out in the following years, but the primary source of contamination at the site came from hundreds of smaller tests conducted until 1963, which involved concentrating radioactive materials like plutonium in specific areas. In 1995, seven British nuclear bombs were buried 16 meters underground at Maralinga. The plutonium used in these bombs has a half-life of 24,100 years, meaning it will remain radioactive for tens of thousands of years. The land was returned to the Maralinga Tjarutja, an Indigenous group from the southern Pitjantjatjara region, in 1985—ten years before the cleanup was completed. However, the return of the land did not mean it was safe. A royal commission led by Justice McClelland found that some areas still had significant nuclear contamination. The full decontamination project, including the burial of the seven bombs, wasn’t completed until 1995. In the meantime, families began to settle in the area in 1985, living on the returned land even as the cleanup was still underway. Today, the Maralinga Tjarutja live in a community called Oak Valley, located about 128 kilometers northwest of the original test site. Oak Valley includes a school and other community facilities, and the people live on land that, while administratively tied to the test site, is not directly on the areas where nuclear waste was buried. The connection to Maralinga remains strong, however, both historically and in terms of ongoing environmental concerns. In 2021, researchers from Monash University published a study in the journal Scientific Reports that analyzed "hot particles"—tiny radioactive grains found in the soil since the nuclear tests. These particles, formed from molten metal droplets in the explosion cloud, were found to be more complex than previously thought. The study suggests that these particles may release small amounts of plutonium and uranium over time, which can be carried by wind and water, inhaled by people and animals, or absorbed by plants. Scientists are still learning how plutonium interacts with these particles and how it might slowly escape over time. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) states that most areas at Maralinga are now safe for activities like hunting, mining, and construction, as they meet decontamination standards. However, a restricted-use zone around Taranaki, one of the former test sites, remains off-limits to permanent occupation. These restrictions are meant to prevent accidental exposure and to contain any remaining contamination. The restricted area is marked with concrete signs in the middle of a now-reopened desert, where wildlife and vegetation have returned. Researcher Megan Cook, who led the 2021 study, acknowledges that Maralinga is one of the best-monitored nuclear test sites, but she also notes that it is impossible to remove every last trace of contamination. "It is never possible to collect every last grain of contamination—it is simply not possible," she said.