Project 4.1

Project 4.1 was the designation for a medical study and experimentation conducted by the United States of those residents of the Marshall Islands exposed to radioactive fallout from the 1 March 1954 Castle Bravo nuclear test at Bikini Atoll, which had an unexpectedly large yield.

[3]As a Department of Energy Committee writing on the human radiation experiments wrote, "It appears to have been almost immediately apparent to the AEC and the Joint Task Force running the Castle series that research on radiation effects could be done in conjunction with the medical treatment of the exposed populations.

In July 1954 a meeting at the Division of Biology at the U.S. Atomic Energy Commission decided to complete 6- and 12-month follow-up exposure studies, some of which were later written up as addendums to Project 4.1.

Barton C. Hacker, the official historian of U.S. nuclear testing exposures (who is, in the end, very critical of the U.S. handling of the Bravo incident), characterized the controversy in the following way: In March 1954, the AEC had quickly decided that learning how the Marshallese victims of Castle Bravo responded to their accidental exposure could be of immense medical and military value.

This unfortunate choice of terminology may help explain later charges that the AEC had deliberately exposed the Marshallese to observe the effects.

Like the American radium dial painters of the 1920s and the Japanese of Hiroshima and Nagasaki in 1945, the Marshallese of 1954 inadvertently were to provide otherwise unobtainable data on the human consequences of high radiation exposures.

[9]Controversy continues however, fed by the legacy of mistrust sown by American nuclear testing in the Marshall Islands, which involved relocating hundreds of people and rendering several atolls uninhabitable.

In these ways, the study of the exposed Marshallese reflects the same ethical lapses as were undertaken in other aspects of the secret human radiation experiments conducted by the Atomic Energy Commission in the 1940s and 1950s, which came to light only after the end of the Cold War.

Though the Marshallese experienced far milder immediate effects than the Japanese fishermen exposed to Bravo fallout on the fishing boat Daigo Fukuryū Maru, the long-term effects were more pronounced as they depended largely on subsistence living and were relocated to the site of the testing in Bikini, Ene Wetak, and Rongelap while the Japanese fisherman were returned to Japan.

For the first decade after the test, the effects were ambiguous and statistically difficult to correlate to radiation exposure: miscarriages and stillbirths among exposed Rongelap women doubled in the first five years after the accident,[medical citation needed] but then returned to normal; some developmental difficulties and impaired growth appeared in children,[medical citation needed] but in no clear-cut pattern.