Radioactive particles can be carried for considerable distances . Radiation from the Trinity test was washed out by a rainstorm in Illinois . This was deduced , and the origin traced , when Eastman Kodak found x-ray films were being fogged by cardboard packaging produced in the Midwest . Unanticipated winds carried lethal doses of Castle Bravo fallout over the Rongelap Atoll , forcing its evacuation . The crew of Daigo Fukuryu Maru , a Japanese fishing boat located outside of the predicted danger zone , was also affected . Strontium-90 found in worldwide fallout later led to the Partial Test Ban Treaty
Castle Bravo
Castle Bravo
Mushroom cloud