1.1
Nature of the Event and Description of the Exposed Groups
FouLtow1ne THE Detonation of a nuclear device at the Pacific Proving ground in the Spring
of 1954, significant amounts of radioactive material fell on neighboring populated atolls.
The Marshallese inhabitants of Rongelap atoll
(designated as Group I) received the highest
calculated dose of radiation.
Some of the
Rongelap people were located temporarily on
Ailinginae atoll from the time of the fallout
until they were evacuated (Group IT). ‘Their
calculated dose was smaller than that of the
other members of the parent group. The
American service men (Group III) were located on Rongerik atoll. The largest group of
Marshallese (Group IV) were located on Utirik
atoll and received the smallest dose. The Marshallese were living underrelatively primitive
conditions in lightly constructed palm houses
(Fig. 1.1).
The American military personnel had the
second highest exposure. They were more
aware of the significance of the fallout than
were the Marshallese, and promptly put on ad-
ditional clothing to protect their skin. As far
as duties would permit, they remained inside of
aluminum buildings. In contrast, most of the
Marshallese remained out-of-doors and thus
were more heavily contaminated by the ma-
terial falling on the atolls.
Some of the
Marshallese, however, went swimming during
the fallout and manyof the children waded in
the water, thus washing a considerable amount
of the material from their skin.
The exposed personnel were evacuated to
Kwajalein by air and surface transportation.
Since a survey of all individuals showed that
there wassignificant contamination of skin, hair
and clothes, prompt decontamination was instituted. Clothes were removed and laundered
and repeated washings of the skin and hair
with fresh water and soap were carried out. In
many of the Marshallese, it was difficult to wash
the radioactive materia] from the hair because
of the heavy coconut-oil hair dressing.
The exposure groups with individuals involved, the calculated doses of radiation, the
probable times of beginning of the fallout and
the evacuation times are given in T le 1.1.
Table 1.1—Exposed, and Control Unexposed Groups
Group Drsicnanion
Noman
In Group
Group I.—Rongelap
“
Group I.—Ailinginae
64
|
18
Group ITI.—Rongerik
,
28
Group [V.—Utirik
|
157
Marshallese, Control
Group A
Americans, Control Kwa- |
jalein- American
117
APPROXIMATE
eeoFcom
FaiLout
Time or Evacuation
|
H + 4to6
hrs.
H+4to6/
hrs.
H+ 6.8hrs.|
H + 22 hrs.
Started at H + 55 hrs.
Completed at H + 78 hrs.
|
I
Total Exposed—267; Total Controls—222
H + 50 hrs. (16 people)
H + 51 hrs. (48 people)
H + 58 hrs.
.
H + 28.5 hrs. (8 men)
H + 34 hrs. (20 men)
UseinDoseCrucu.
atureor°
aerate
LATIONS
Doss in
375 mr/hrs.,H + 7|
days
100 mr/hrs., H + 9
days
280 mr/hrs., H + 9
days
175
40 mr/hrs., H + 8
days
Aim(¢}
69
78
14