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SECRET
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BECLASS
Based on the Bikini experience and the forecast 72-hour air particle
trajectories, NYKOPO Flight Able was scheduled for 30 March to assess the
“SSF 0
effects of secondary fall~<mnit on the atolls east of Bikini.
Rate ooo.
On 30 March a report wes received from CIG 7.3 to the effect that no
early fall-out was received by any ship except the experimental YACts, that
mearly all ehips and boats received light contarination from fall-out occur~
ring approximstely 4O to 48 hours after ehot time, that average readings of
25 mr/hr were reduced due to decontamination and decay, that personnel ex-
posures ware negligible compared with BRAVO {estimated average additional
individual exposures due to ROMEO was approximately 50 mr), and that, although
the western quarter of the Lagoon was still highly contaminated, it was doubtful if lagoon contazination would become a eerious probler to ships. The
above information was pessed on 31 March to CINCPACELT in accordance with
@ post -BRAVO request by CINCPACFLT for such information.
On 31 March information was received from the 16 7.3 unit on Kwajalein
to the effect that 9 mr/hr meximms were observed om the windward side of
tree trinks, 1 tc 3 mr/br averzge an beaches and 1 to 4 mr/hr average an
windward sides of buildings.
Merch was 0.05 m/hr.
The average Ewejelein backgr.umd prior to 31
The advisory further stated that aircraft on training
flights in the local area were concentrating contamination reaching mximx
velues of 20 m/hr an engines. (Note: Approximately the same velues were
observed at Exiwetok by the evening of 29 March. Values were § mr/hr average,
with 15 mr/hr maximm on windward @urfaces. )
On 1 April a speéial radsafe advisory was dispetched tc ComiavSte Kwa ja-
lein tc reassure the garrison relative to the light fall-out experienced.
This advisory noted that the fall-out cn Ewejalein was cf a degree equivelent tc thet experienced on Eriwetok and considered insignificant from a
he2lth standpoint. As a precautionary measure, it was suggested that Kwejaleiz water catch basins be examined carefully, the first run-off of the next
rein be isolated and that a pint sample be taken for analysis. The facili-
ties of the teak force were made available (and accepted) for this analysis.
(Subsaquent analysis indicated no activity in the five samples taken except
the one from Open Storage Tank No. 10 which read 4.85 x 10 microcuries
per milliliter.)
On 3 April in response to a request from Kwajalein the above adrisory
wes re~quoted to include CINCPACFLT, and further stated that the Tesk Force
Staff Surgeon would wisit Kwajalein to establish suitable operating proced-
ures for future shots.
of the CASTLE series.)
(No further difficulties arose for the remainder
On § April informetion wes received thet wire services were carrying
Toky- stcriss reporting two depansse fishing vessels outside the Danger Ares
erriving at port with radioactive tuna. These stories indicated that some
af the catch was destroyed, vessels reportedly radioactive, but no iliness
reported on the crews, Wo official confirmation wes received, and from the
presse stories the contamination appeared to be slight. Considering time and
distance factors, the contamination could have came from ROMED at fishing
grounds to the east northeast of &.
SECRET
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DECLASSIFIED
RESTRICTED DATA
ATOMIC ENERGY ACT — 1946
PN
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