personnel who exceeded the 3.75 and 5 R limits. Military personnel were to be advised that
they should not be exposed to further radiation until sufficient time elapsed to bring their
average radiation exposure down to 0.3 R/week.
Civilian personnel in this category were to
be informed that limitations of further radiation exposure were to be determined by the
laboratory or agency having administrative jurisdiction over such personnel.
A film badge program provided an exposure-indicating device to all JTF 7 personnel to
maintain complete exposure information on everyone entering the EPG during the operation.
The commander of the scientific task group assigned overall badging responsibility to a
special task unit.
Beginning 1 April 1958, film badges were issued to all individuals upon
their arrival at the EPG with instructions that the badge be worn at all times and turned in
on recall, upon exit from any contaminated area, or upon departure from the EPG.
SUMMARY OF TASK FORCE EXPOSURES
The table on the following page documents the numbers and percent of task force personnel who received exposures in various categories.
These data are based on the latest data
available and may be added to as research is completed. Of the some 19,600 individuals badged
at HARDTACK, 99 percent had exposures that did not exceed the current Federal guidelines of 5
R per year. The highest recorded exposure for the series was 12.41 R. The overall joint task
force mean exposure was 0.87 R.
During the conduct of the series only one incident occurred of an exposure of a large
group of JTF 7 personnel to significantly elevated radiation levels. This happened on 14 May
when the base islands (Enewetak and Parry) at Enewetak Atoll received fallout from a test
shot that had been detonated at Bikini two days before.
This fallout episode, which lasted
about 60 hours, could have contributed as much as 1.2 to 1.5 R total dose to personnel on
Enewetak Atoll depending upon the island on which they lived and their work activities.
However, since nearly all personnel wore film badges, this fallout exposure is reflected in
the film badge doses.
There was one known incident of offsite fallout. Two Japanese research vessels operating outside the danger area set up around the EPG detected an increase in radiation after shot
POPLAR. An investigation by the JTF 7 Staff Surgeon revealed that this exposure was small,
amounting to, at most, 0.085 R for the crew, and even this figure did not reflect the
decontamination procedures that were used to lower the contaminaticn.
The detonations during HARDTACK I,
the Hawaiian Islands to fallout.
including
those at Johnston Island,
did not expose