Between 1977 and 1980, the United States enlisted roughly 4,000 U.S. soldiers and subcontractors to clean the site. Many said they were inadequately protected. They excavated soils from Enewetak and elsewhere and turned the soil into a concrete slurry, which they poured into an unlined crater on Runit Island, left behind by the Cactus bomb. They sealed it with a clean concrete top 18 inches thick, creating what is now called the Tomb.

Source: Los Angeles Times May 28, 2019 12:00 UTC