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JOINT TASK FORCE’ SEVEN
TASK GROUP 7,3
APO 187, c/o Postmster
San Francisco, California
From:
Tos
Via:
“7O
FF3/7.3/32:mf
J15-9
Ser: 00666 *
76555
Conumander, Task Group 7.3
Chief of Naval Operations
(1) Commander Joint Task Force SEVEN.
(2) Commander in Chief, U.S. Pacific Fleet
Subj: ‘Radioactive Contamination of Ships and Radiological Exposure of ‘Personnel , .,
of Task Group 7.3 dus to BRAVO, the First Nuclear Fixplosion of CASTLE =: .
.
Ref: (a) CTG 723.Conf aizpatch 1307332 of March 195!
Encl:
(1) Diagram indicating positions of TG 7.3 ships from H hour until about.
0815, 1 March 195i.
(2) Tabulation of average topside radioactive intensities of Task Groupe2.3
we
ships, at various times following BRAVO,
(3) Tabulation of accumlated radiological exposures of Task Group 7.38
persomel by ships and units...
(4) -BAIROKO (CVE 115
secret serial 0010 of 11 March 95h a
1. Onl March .195k, at O645M, the first nuclear explosion (ERAVO) of Operation.cae
CASTLE was detonated. Prior to the detonation, ships of Task Group.7,3 had been~:
deployed atsea - generally in the. southeast quadrant from’ ground: zero as indicaped»
in enclosure (1),'» This disposition end its-location were based on four principe.
factors, {a) the. latest CJIF SEVEN radex, (b) the requirements of thé Gonmands
Scientific Task Group (CTG.7,1) that. ESTES (AGC 12) andCURTISS (AV):beeee
a
ed about’ 12 miles from ENYU Island forreliable UHF communications,gnd
purposés, (c) the requirement ‘that ships be disposed at safe ‘aietan
rites(ofee
30 miles) from ground zero;toavoid harmful heat, and blast effécey fata‘thé:
requirementof. reasonable sgoncentration for communicaticns andsontesTe
purposeswe
Prior to the detonation and because leterwinddata began to esRaneasterly -
component; some ofthe ‘smaller ani slower units were directed:to:move:to:the
pouty
but the larger ships were retained inthe localities indicated :in viewpf’
CLASSIFICATION CA
NCELLED
foregoing requirements. (b)and (d)<and the expressed desire of the JIF Commander
that they not be moved,.”:- Because. ofthe additional requirements forearlyheli- ©
copter survey trips and ‘the early“dispatch by helicopter of- an emergency airfield _
crew for the airfield. én EVINMAN Island, the large ships were retained generally
in their pre~shot positions after.the detonation¥
“until: about OS00M, when sudder_
and rapidly increasing radioactive falloutwas detected on. some ships. At this”
time, all ships were-ordered.to take allpossibleradiological-defense damage’:
control measures, Ancluding. the employnpnt‘of _washdown ’ systemsy::anid to proceed |to
the south at best speed,
7K
2. Commencing atout“O800M, highly’ radioactive> visible,» White particles, about the
size of pinheads, began tofall on BATROKO, .PHILIP, ESTES and CURTISS, At this: .
time BATROKO was about 31 miles from ground ZETO»
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