Crumbling Runit Dome Leaks Radioactive Waste as Sea Levels Rise

A concrete dome on Runit Atoll in the Marshall Islands is deteriorating, exposing thousands of tons of radioactive waste left behind by US nuclear tests. The structure, built in the 1980s, now poses growing risks as cracks widen and sea levels rise. Local authorities lack the resources to address the looming environmental threat.

The dome, known as the Runit Dome, was constructed using 358 concrete panels to seal waste in a crater. It followed a US military cleanup after decades of nuclear testing in the region. But by 2013, a US Department of Energy report confirmed radiation was already leaking from the site.

The main danger does not come from the dome collapsing but from waste seeping through the porous limestone beneath it. Rising sea levels and global warming are making the problem worse, increasing the risk of contamination spreading. Meanwhile, the US maintains it has met all obligations and that responsibility now rests with the Marshall Islands—a nation of 53,000 people with limited capacity to manage the crisis.

The Runit Dome continues to leak radioactive material, with no clear solution in sight. Rising tides and eroding concrete threaten to worsen contamination in the coming years. The Marshall Islands faces the challenge alone, as the US denies further responsibility for the site.