Runit Dome (or Cactus Dome), Runit Island, Enewetak Atoll. Aerial view. In 1977-1980 the crater created by the Cactus shot of Operation Hardtack I was used as a burial pit to inter 84,000 cubic meters of radioactive soil scraped from the various contaminated Enewetak Atoll islands. The Runit Dome was built to cover the material