[3][4] From 1977 to 1980, loose waste and topsoil from six different islands in the Enewetak Atoll was transported to the site and mixed with concrete to seal the nuclear blast crater created by the Cactus test.

Concern primarily lies in the rapid tidal response to the height of the water beneath the debris pile, with the potential for contamination of the groundwater supply with radionuclides.

[3] However, as the Department of Energy report stated, the released radionuclides will be very rapidly diluted and should not cause any elevated radioactive risk for the marine environment, compared to what is already experienced.

[10][11] An investigative report by the Los Angeles Times in November 2019 reignited fears of the dome cracking and releasing radioactive material into the soil and surrounding water.

[9] In June 2020, the US Department of Energy released a report stating that the dome is in no immediate danger of collapse or breach and that the radioactive material within is not expected to have any measurable adverse effect on the surrounding environment for the next twenty years.