Cracks in a dome over a contaminated nuclear blast site in the Marshall Islands have raised concerns about a potential leak, which could occur amid rising seas. The dome was sealed with a concrete dome constructed between 1977 and 1980 after the US dropped an 18-kiloton bomb on Runit Island in 1958 as part of a series of nuclear tests conducted on South Pacific Islands. Concerns have grown since this incident, with groundwater already seeping into the crater and experts fear that parts of the nuclear tomb could be submerged due to rising sea levels. Columbia University chemistry professor Ivana Nikolic-Hughes found elevated radiation levels in the soil surrounding the dome and warned that the potential fallout could be 'potentially devastating' given that Runit is just 20 miles from where people live.