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ABSTRACT
Following the detonation of Shot { on Bikini Atoll on 1 March 1954, 28 Americans and 239
Marshallese were exposed to fallout. One hundred fifty-seven of the Miarshallese were on Utirik
Atoll, 64 were on Rongelap Atoll, and 18 were on the neighboring atoll of Ailinginae. The 28
Americans were on Rongerik Atoll. The presence of significant fallout on these atolls was first
determined by a recording dosimeter, located on Rongerik, when this device went off scale at
100 mr/hr shortly after the detonation. Emergency surveys detected radiation on the inhabited
atolls, and evacuation of inhabitants to the Naval Station at Kwajalein was promptly carried out.
The dose of radiation to which the individuals were exposed was calculated fromthe intensities
found on the islands and the decay exponent of the fatlout material. The individuals on Rongelap
received approximately 175 r, those on Ailinginae received approximately 69 r, and the Americans on Rongerik received an average calculated dose of 78 r. The Marshallese on Utirik received approximately 14 r. The fallout on Rongelap, Ailinginae, and to a lesser.extent on Rongerik was distinctly visible. No fallout was observed on Utirik. A significant number of individuals on Rongelap suffered from mild nausea and one or two individuals vomited on the day
of the exposure. With the exception of nausea in one Ailinginae individual, there were no other
definite gastrointestinal symptoms in the other Marshailese or the Americans. The Mar-
De
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Shatlese on Rongelapand Ailinginae, and the Americans experienced to a varying degree burn-
ing of the eyes and itching of the skin from 1 to 3 days. Later, signs of radiation injury included
definite epilation in the Rongelap and Ailinginae groups, and the development of spotly, superficial, hyperpigmented skin lesions that desquamated from the center of the lesions outwards.
In some cases the skin damage was sufficient to result in raw, weeping lesions. There was
no full thickness necrosis of the skin. The Americans developed only minor skin lesions without
ulceration. There were no skin lesions in the Utirik natives. All lesions healed rapidly with
no further breakdownof the skin noted during the period of observation, Microscopic examiunation of biopsies of the lesions showed changes usually associated with radiation injury.
Fully
clothed individuals and those remaining inside of buildings or huts were protected to varying
degrees from development of lesions. Hematologic changes were definite in the Rongelap,
Ailinginae, and the American groups.
Lymphopenia appeared promptly and was persistent for
a prolonged period of time. Neutropenia occurred in all of the individuals with initial minimum
values occurring around the llth day followed by an incrnase in the counts and a secondary
minimumaround the 40th to 45th day. The most consistent hematologic change was the depression in the platelet counts. Platelets were below normal when first counted on the 10th
day of post-exposure and progressively decreased attaining a minimum between the 25th and
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30th day, Although recovery commenced following this minimum, the platelet counts had not
returned to normal by the completion of the initial study on the 76th post-exposure day. The
incidence of various respiratory and culaneous infections was identical in all exposure groups
and bore no relationship to the hematologic changes.
,
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Urinary excretion of radioisotopes was studied. Small amounts of radioactive material
were found. Estimates of total body burden indicate that there is no long term hazard and that
ingestion and inhalation of isotopes did not contribute significartly to the initial radiatoon
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exposure.
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