2.2.1 Enewetak Atoll.

Of the six shots, BRAVO, ROMEO, and NECTAR caused measurable fallout on

the residence islands of Enewetak Atoll. Generally, such fallout was secondary (onset
was well after the time of detonation) and relatively minor in nature. At the time it
was considered a "nuisance factor" (Reference 12).

Fallout on Enewetak from Shots

UNION and YANKEE was apparently even less significant as evidenced by the

conflicting reports of the minor contamination following these two shots (References

10 and 14).
Fallout from Shot BRAVO began on Enewetak at approximately 1745 hours on
1 March,

11 hours after the shot (Reference

10).

Soon after, average gamma

intensities were 3-4 mR/hr and by 2300 hours, when fallout stopped, average
intensities were 10 mR/hr with a maximum intensity of 15 mR/hr being reported.
Figure 2-3 depicts the free-field radiation intensity on the residence islands (Parry and
Enewetak) of Enewetak Atoll.

Radioactive decay after 2300 hours is inferred from

decay rates measured during the same time period on Bikini Atoll.
Fallout on Enewetak from Shot ROMEO came in two distinct "waves".

It began

at approximately 1700 hours on 27 March and peaked at 2100 hours with average
intensities of 3 mR/hr being reported on Parry Island (Reference 12). Another period
of fallout began during the late evening of 28 March and did not peak until noon on
30 March, at which time the average island intensities were approximately 9 mR/hr;

maximum intensities were reported to be 15 mR/hr. Figure 2-4 depicts the radiation
intensity for Enewetak Atoll.

‘It is seen from the figure that BRAVO fallout

contributed but little to the intensity after Shot ROMEO.

The TG 7.2 unit history for Operation CASTLE (Reference 14) indicates that
Enewetak Island may have received contamination following Shots UNION and
YANKEE.

It states, "The radiation level, however, did not become significant.

Following UNION, a peak intensity of four milliroentgens per hour (mR/hr) was
received, and following YANKEE, the peak reading was only one mR/hr.”

Although

these levels are not high, they are contradictory to those given in the JTE-7 rad-safe

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