The United States conducted dozens of nuclear tests in the Marshall Islands, which are part of the collection of islands that form Micronesia, between 1946 and 1958. For their part, locals were moved out of the area and were unable to return for over 30 years. The majority of testing took place on Enewetak Atoll and Bikini Atoll, an area located between Hawaii and Australia. The islands were picked for several reasons: 1) their remote location, 2) their distance from large populations of people, and 3) their lack of proximity to shipping lanes.
During this time period, 67 nuclear and atmospheric bombs were tested. In 1958 alone, the Pacific Proving Grounds were subject to 35 nuclear tests. After testing was completed, there was a massive amount of radioactive waste left over. Environmental concerns and fears of nuclear contamination spurred the US government to try and clean up the Pacific location – sort of.
Maintaining the Enewetak atoll cleanup has become pretty difficult, and this is really troubling because of the deterioration of something called the Runit dome on Runit Island. The Runit Dome was built by the US Army inside a crater in order to contain the toxic waste. But, as ocean levels rise, there has been a growing concern over the Runit dome leaking – the consequences of its failure, which would mean nuclear waste seepage, could be disastrous.
After the US Defense Nuclear Agency (DNA) completed its nuclear testing in the area, the agency spent nearly 10 years trying to clean it up. When Congress decided it didn't want to pay to make the area habitable again, the agency considered its options. Their first choice was dumping the waste into the sea. However (thankfully), the agency was blocked by international accords and other regulations concerning hazardous waste. And nobody wanted to move the radioactive waste to the United States. What to do?
Rather than dumping nuclear waste into the ocean, the US government thought filling a huge crater and building a dome over top of it might be the ticket. So, in the 1970s, the US government chose Runit Island to store 111,000 cubic yards of the radioactive debris leftover from nuclear testing. The area contained an enormous crater, which resulted from a test that was performed in 1958, and they decided to dump the waste into it. The Army built a concrete dome topped by an 18-inch cap over the 33-feet-deep crater to prevent material from leaking into the ocean. Locals call it "The Tomb." Inside, the Army placed soil contaminated by plutonium as well as nearly 437 bags of actual plutonium that were left over after one bomb didn't fire correctly. The waste was sealed under 358 panels made of concrete.
The Army thought it was a good idea to conceal radioactive waste in the crater, but not all the debris was secured there. Some waste had less plutonium contamination, so the military used equipment to push it into the nearby lagoon instead. The Environmental Protection Agency and locals living in Enewetak were not happy with this decision for obvious reasons. Despite their disapproval, the Army went ahead with its plan. The US government also allowed the radiation levels on the land to be much higher in the Marshall Islands than it would have permitted if nuclear testing had occurred on US soil.
A 2013 inspection revealed that the Runit dome is decaying. The groundwater is radioactive, and sand has penetrated the structure. There are also several cracks on the dome, and vines are growing inside the crevices. If all this organic matter is penetrating the structure so easily, what of the radioactivity that it conceals? Eventually, the dome and the land around it could be underwater, or it will be destroyed by storms. Subsequently, radioactive material will leech into the ocean.