When the United States government tested out nuclear weapons, they often tried to do it far away from any place that could potentially harm humans. At least, usually. During the Castle Bravo Nuclear Test, they managed to test out an effective bomb at Bikini Atoll in the Marshall Islands. It worked better than assumed, but the impressive yield led to several Marshallese being exposed to massive amounts of beta and gamma radiation.
[Image via Australian Institute of International Affairs]The test happened on March 1, 1954. A few days later, the U.S. Government began Project 4.1. This was a medical study where the U.S. tested the residents on the Marshall Islands to see how the radiation exposure affected them. Studies on humans like this are controversial, so it was “top secret” for a very long time. Roughly 239 Marshallese were exposed to the high radiation from Castle Bravo. While most believe this was an accident that the U.S. just took advantage of for testing, many Marshallese believe it was planned from the start.