Under the dome: Fears Pacific nuclear 'coffin' is leaking
As nuclear explosions go, the US "Cactus" bomb test in May 1958 was relatively small -- but it has left a lasting legacy for the Marshall Islands in a dome-shaped radioactive dump.
The dome -- described by a UN chief Antonio Guterres as "a kind of coffin" -- was built two decades after the blast in the Pacific ocean region.
Coffin may bleed
The US military filled the bomb crater on Runit island with radioactive waste, capped it with concrete, and told displaced residents of the Pacific's remote Enewetak atoll they could safely return home.
But Runit's 45-centimetre (18-inch) thick concrete dome has now developed cracks.
A symbol of US mess
The concerns have intensified amid climate change. Rising seas, encroaching on the low-lying nation, are threatening to undermine the dome's structural integrity.
The dome has become a symbol of the mess left by the US nuclear test programme in the Marshall islands when 67 bombs were detonated between 1947-58 at Enewetak and Bikini atolls.
A legacy of distrust
After the US military withdrew, the Marshall Islands government officially accepted a "full and final" settlement to cover the impact of the nuclear tests.
But there have long been complaints that the compensation paid by Washington was inadequate, and the United Nations has described "a legacy of distrust" towards the United States.
Numerous islanders were forcibly evacuated from ancestral lands and resettled, including Enewetak's residents. Thousands more islanders were exposed to radioactive fallout and suffered health problems.
The people of Enewetak were allowed home in 1980, and about 800 islanders now live in the southern part of the atoll, 20 kilometres (12 miles) from Runit.