Between 1948 and 1958, the Enewetak Atoll was used by the US government to test 30 megatons of nuclear weapons, which is the equivalent to 2,000 Hiroshima blasts. More than 8,000 people later worked hard to clean up that island, shifting 110,000 cubic yards of radioactive debris into a 30-foot-deep crater, which was later sealed in a concrete dome to prevent contamination.

Paul Griego, who took part in the cleanup and blames the radiation for a host of health problems, said the dome was never fit for the purpose of containing radioactive waste. Although the dome is 16 inches thick, and 350 feet across, Griego says it's nothing more than a "gigantic radioactive toilet."

"We were given an impossible task – cleaning up the radioactive fallout from 43 nuclear bombs. When I first arrived, the dome's blast crater was open to the ocean – it continued to be full of sea water even after it was sealed off from the ocean. During my 10-hour work day, I witnessed the water level in the crater rise and lower as the tide came in and out," says Griego.

The dome is now weathered by decades of exposure to winds and rain, and the radioactive material inside. It's feared that rising seas and storms could see all the radioactive material pour into the ocean. "No attempt was made to drain the crater or line it before the radioactive waste was dumped into it. The coral that created the island is porous and the shock from numerous nuclear weapon tests had also fractured the coral," Griego said. "From the first day forward, the water has flowed out of the lagoon with the tide, creating a gigantic radioactive toilet that is flushed about twice each day into the Pacific Ocean."