time of entry.
This time delay was caused by the practice of issuing film badges at Eniwetok and developing
the film at Bikini and by a lack of night transportation
in the lagoon.
The practice of entry control by film-badge exposures
left much to be desired, but it was the only method avail-

able in the absence of reliable self-reading dosimetric

devices.
The practice of issuance and development of film
badges may have penalized many individuals because of inherent inaccuracies of the film badge in the presence of
low-energy radiation and low dosages.

PRE-EVENT SAFETY MEASURES

Hazard Zones
A security zone, 150 x 300 nmi

(278 x 556 km), was established around

Enewetak and Bikini prior to CASTLE (Reference 26),* and this also served
as a radsafe precaution area.

The area was patrolled by P2V aircraft and

destroyers to assure that no unauthorized vessels were present.
also diverted shipping from within a sector 500 nmi

(926 km)

The Navy

from ground

zero in an are extending from the southwest, clockwise to the east.
volving primarily U.S.
H+24,

In-

shipping, this was done on all shots from H-hour to

‘

After BRAVO, maximum cooperation with other nations was sought to control shipping in the hazard zone.

The area was officially designated a

danger zone and redefined as the sector centered on 12°N, 164°E, from 240°

clockwise to 95°, with a radial distance 450 nmi (833 km).
(designated Area Green)

A subsector

was defined as the region bounded by 10°15'N,

16°40'N, 160°10'E, and 170°20'E, which was subject to more intensive air
and sea search prior to a shot than the rest of the danger zone.

Addi-

tionally, all U.S. shipping that passed within 600 nmi (1,111 km) of Bikini came under the operational control of CTG 7.3

(for radsafe diversion

if necessary).

* The area was bounded by 160935' to 166°16’E and 10°15' to 12°45'N.
107

Select target paragraph3