One of these many tests , the March 1 , 1954 , explosion of Castle Bravo , a U.S. thermonuclear device , was responsible for most of the radiation the Marshall Islanders were exposed to . The fallout-related doses of this single test are believed to be the highest recorded in the history of worldwide nuclear testing . Many of the Marshall Islands which were part of the Pacific Proving Grounds remain contaminated by nuclear fallout , and many of those downwinders who were living on the islands at the time of testing have suffered from a highly increased incidence of several types of cancers and birth defects
Castle Bravo
Castle Bravo
Downwinders