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Cactus Dome

An enormous concrete structure built over a nuclear crater

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Category Ghost Towns, Disaster Areas, Subterranean Sites

Image of Cactus Dome located in Marshall Islands | a

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Between 1946 and 1962, the US military conducted 105 atmospheric nuclear tests over the "Pacific Proving Grounds," a euphemism for the Marshall Islands and several other nearby South Pacific atolls.

In the late 1970s, in an effort to clean up the radioactive debris left by those explosions, the US government dug up 111,000 cubic yards of soil from the Bikini and Rongelap atolls and deposited it on Runit Island. Its resting place would be in a 350-foot wide crater that had been created two decades earlier by an 18-kiloton nuclear test code-named Cactus.

Covering up that giant radioactive pit cost the government nearly a quarter of a billion dollars and took three years to complete. The result: an enormous, foot-and-a-half-thick, 100,000-square-foot dome consisting of 358 gigantic concrete panels. Despite signs warning off visitors, it is still possible to make landfall on Runit and stomp across the Cactus Dome. Bring a Geiger counter.

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Address Runit Island, Marshall Islands

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Comments

Anonymous October 27, 2011

I don't think I would be to quick believe much of anything the the U.S. Government says in terms of safety bulletins regarding prior military operations and or nuclear testing sites. Obviously they will tell you what they want you to believe be it truth or otherwise, common sense and independent sources will probably take you a lot closer to the truth. If I remember correctly this was covered pretty well in National Geographic which stated they used a lot of "Local People" in the clean up, most of which have died from various types of cancer etc in the years since, which has been a pretty big thing in the years since. Believe what you will but I think to outright believe these places are safe is probably pretty naive. I love my country as much as the next guy and was in the U.S.M.C. but we are at a point where we must question everything they try to feed us now days as they don't even try to hide their lies and corruption anymore. Great site with cool stuff ! Thanks.
A Facebook user May 10, 2011

A few things to consider: the United States declared Runit safe for habitation in 1980, and both Hiroshima and Nagasaki have been continually inhabited since WW2. Note that I'm writing this from Tokyo post-Sendai quake, and the potential nuclear scare re: the Fukushima plant has, for lack of better terminology, generally blown over.
Anonymous November 5, 2009

How was the soil collected? And how was the containment dome built by workers to avoid the radioactivity?
Anonymous August 29, 2009

I believe the circle off the coast is another bomb crater. They did many tests there.
Anonymous August 8, 2009

Be aware they also did underwater testing multiple times, so it may actually be an artifact (read crater) from one of the tests.
admin August 3, 2009

I believe that is a blue hole, that just happens to be nearby the dome. I saw it too, it is quite a coincidence!
Anonymous August 1, 2009

When I look at this on google earth there seems to be a similarly sized circle in the water off the coast near the dome. Does anybody know what this is? I assume it is something from the construction of the dome.
Anonymous June 23, 2009

I think you mean, "not immediately fatal". That's always been the kicker with radiation poisoning.
argontus June 22, 2009

Hi Josh, the half-life of Uranium-235 is 700 million years and below the concrete there is a lot of very contaminated soil, which has come in contact with nuclear fallout from numerous nuclear tests (weapons-grade U-235 and U-238). Despite the enormous size of the concrete dome, it is not very thick and won't stop all the radioactive particles, especially the gamma type. So bringing a Geiger counter when trekking in that area would be a good idea indeed. Looking at the picture above, there are however people walking on top of the dome, so the radiation is probably not fatal. :)
Josh April 12, 2009

Is the Cactus Dome still radioactive? How dangerous is it, actually?