MARCH 1957 MEDICAL SURVEY OF RONGELAP AND UTIRIK PEOPLE
THREE YEARS AFTER EXPOSURE TO RADIOACTIVE FALLOUT
Background
This report presents the results of a medical
survey carried out in March 1957 on the Marshallese people who were accidentally exposed to

radioactive fallout in March 1954. The accident
occurred following the detonation ofa large thermonuclear device during experiments at Bikini
in the Pacific Proving Grounds. An unpredicted
shift in winds caused deposition of significant
amounts of fallout on four nearby inhabited Marshall Islands and on 23 Japanese fishermen aboard
their fishing vessel, the Lucky Dragon. Sixty-four
inhabitants of the island of Rongelap, 105 nauti-

cal miles away from the detonation, received the
largest fallout exposure among the inhabited

islands: an estimated dose of 175 r whole-body
gamma radiation, beta lesions of the skin, and

epilation from contamination of the skin and

slight internal absorption of radioactive material.

The Japanese fishermen probably received a similar exposure, although estimation of their dose

is much less certain. Also 18 Rongelap people
awayon a nearby island (Ailingnae), whereless

addition examinations were carried out on an unexposed comparison population.
SUMMARY OF PAST FINDINGS

The following is a brief summaryof the past
findings which can be foundin detail in the references.’-?"°
Duringthefirst 24 to 48 hr after after exposure,
about two-thirds of the Rongelap people experienced anorexia and nausea and a few vomited
and had diarrhea. At this time manyalso experienceditching and burning of the skin and a few
complained of lachrymation and burning ofthe

eyes. Following this, the people remained asymptomatic until about two weeksafter the accident,

when cutaneouslesions andloss of hair developed,
due largely to beta irradiation of the skin. The
effects of the radiation can best be summarized
under three headings according to the mode of
irradiation: penetrating irradiation, skin irradiation, and internal irradiation.

Penetrating Irradiation

fallout occurred, received only about halfthis exposure. Twenty-eight American servicemen on an

The people on theisland of Rongelap received
an estimated whole-body dose of 175 r gamma
radiation. Depression of peripheral blood elements occurred asfollows (see Figures 7-15):
Lymphocytes fell promptly and by the third day
were 55% of control values (unirradiated Mar-

not visible on this island and noskin effects were
seen.

There was only slight recovery by six months.
Through the two-year examinations the mean
values of these cells werestill below the control
levels. At two years the lymphocytes were about
75 to 80% of the mean level of the comparison
population.
Neutrophils fluctuated considerably during the
first few weeks but fell gradually to a low of about
50% of control values by the sixth week after ex-

island (Rongerik) further away received about the
same amount of radiation as did the 18 people
on Ailingnae. Lastly, 157 Marshallese on Utirik
Island, some 200 miles distant, received only
about 14 r whole-bodyradiation. The fallout was

The initial findings have been reported on the
Marshallese and Americans’ and the Japanese

fishermen.” Subsequent examinations of the
Rongelap people have been reportedatthe follow-

ing times after exposure: six months,’ one year,’
and twoyears.’ The present report concernsthe

examination of the Rongelap and Utirik people
three years after exposure to fallout radiation. In

shallese) in adults, and about 25% in children.

posure; recovery was slow. At six months counts

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