Rongelap Atoll
Rongelap Atoll is an uninhabited coral atoll comprising approximately 61 islets in the Ralik Chain of the Marshall Islands, with a total land area of about 9 km² enclosing a lagoon of roughly 1,000 km².[1] The atoll's defining historical event occurred on March 1, 1954, when unexpected winds carried radioactive fallout from the U.S. Castle Bravo thermonuclear test—yielding 15 megatons at Bikini Atoll—onto Rongelap, exposing its roughly 82 residents (including those on nearby Ailinginae Atoll islets) to acute gamma radiation doses averaging 1.9 Gy whole-body, alongside substantial internal contamination from ingested and inhaled fission products.[2][3] Evacuated by U.S. forces three days post-detonation after symptoms like nausea and skin burns emerged, the population was resettled in 1957 following surveys deeming conditions habitable, but persistent radionuclide uptake via local food chains prompted health concerns including elevated thyroid abnormalities and cancers, leading to self-exile in 1985 aided by Greenpeace.[4][5] Today, Rongelap remains unpopulated, with soil and coconut crabs showing cesium-137 concentrations in some areas rivaling or exceeding those in Chernobyl-impacted regions, though external gamma levels have decayed to background equivalents on many islets per recent dosimetry.[6][7][8]