During the Cold War, the United States nuked the Marshall Islands 67 times. After it finished nuking the islands, the Pentagon dropped biological weapons on the islands. Once the U.S. was finished, it scooped the irradiated and ruined soil from the islands, poured it into a crater left behind from a nuclear detonation, mixed it all with concrete, and covered the whole thing in a concrete dome. They called it “The Tomb.” According to a report from The Los Angeles Times, climate change is breaking that dome open. Rising sea levels and temperatures are cracking open The Tomb, threatening to spill nuclear waste into the Pacific Ocean.

The Marshall Islands is a collection of 29 atolls across 1,156 islands. More than 50,000 people live on the islands. From 1946 to 1958, it was a proving ground for America’s nuclear arsenal. On March 1, 1954, the Pentagon conducted Castle Bravo and detonated a 15 megaton thermonuclear warhead over the Bikini Atoll. It was the largest nuclear weapon the U.S. ever detonated.

The fallout from the explosion rained down on the people of the Marshall Islands.

“It was only a matter of two or three years before women on the island started to give birth to things less than human,” a Marshall Islands woman told diplomats on a fact finding mission decades later. Birth defects are so common on the islands that the people have a number of words to describe them, among them marlins, devils, jellyfish children, and grape babies.

The U.S. has largely dismissed its responsibility to the Marshall Islands. It relocated many of its people and claims the cost of relocation and installation of The Tomb at the Enewetak Atoll covers its liability. As sea levels and temperatures rise, however, the Tomb is cracking. As it cracks, water rushes over it, leaching out plutonium and dumping it into the sea.

The U.S. has said The Tomb is now the Marshall Islands’ responsibility.

“I’m like, how can it [the dome] be ours?” Hilda Heine, the president of the Republic of the Marshall Islands, told The Los Angeles Times. “We don’t want it. We didn’t build it. The garbage inside is not ours. It’s theirs.”

"It's hard to imagine that the U.S. would consider its actions sufficient if the roles were reversed,” Alex Wellerstein, a nuclear historian at Stevens Institute of Technology, told Motherboard in a Twitter DM. “That somehow the world's richest nation can't seem to find the political will to make things right with a small, poor nation that sacrificed much in the name of American national security is a travesty. U.S. officials in the Cold War were quick to talk about how important the testing was to American survival, but somehow that importance never translated into a sincere gratitude to the suffering Marshallese."

The Tomb contains not just the irradiated soil and metal scrap from the Pacific proving grounds, but also 130 tons of soil shipped in from Nevada. The Pentagon buried not only the nuclear waste and byproduct of the Marshall Islands, but shipped in extra from out of town. A study by Columbia University researchers in July showed that regions of the Marshall Islands are more radioactive than Chernobyl.

The Nuclear Claims Tribunal, an independent ruling body with the authority to arbitrate legal relations between the United States and the Marshall Islands, awarded the Marshall Islands $2 billion in damages in 2001. Washington has paid only $4 million. At the time of its construction, a Lt. General for the U.S. Air Force said that, should the dome ever fail, it would be America’s responsibility to fix. Terry Hamilton, a researcher at Lawrence Livermore National Laboratory and the Department of Energy’s Marshall Islands expert told The Los Angeles Times that “Under existing living conditions, there is no radiological basis why I or anyone else should be concerned about living on Enewetak.”

“The experts who assert that any given place is safe-enough to live never seem to live in such places themselves,” Wellerstein said. “I think it's easy to be confident about your data and look over the possible uncertainties when you don't personally suffer the consequences if you're wrong.”