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The Honorable Paul G. Rogers
House of Representatives
Washington,
D. C. 20515

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Dear Mr. Rogers:
On behalf of the Secretary of Defense, I am pleased
to respond to your letter of April 21, 1978, concerning
radiological
safety aspects of DOD’S
role in the cleanup
project for Enewetak Atoll.
In the six years since inception of the project, no facet of planning and execution
has received more intense and continuing emphasis than
radiological
safety measures to protect those carrying out
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the cleanup.
Before responding to your specific questions, let me
offer to brief you and your staff in person on the cleanup
and related health physics considerations.
I believe such
a briefing would provide you a deeper understanding
of the
extraordinary
radiological
safety precautions that have
been in effect from the outset, and would give you the
opportunity
to satisfy “yourselves, through detailed questioning, of specific matters that might not have been touched
upon in your questions or in the answers provided herein.
As background for addressing
the specific issues, it
might be useful briefly to review the history of this operation.
In 1947 the people of Enewetak Atoll were relocated to Ujelang
Atoll so the United States could use Enewetak for nuclear
weapons tests.
Forty-three
nuclear detonations
took place
at Enewetak between 1948 and 1958.
In 1972 Ambassador Williams announced that the United
States was prepared to clean up, rehabilitate~
and return
the Atoll to its people.
At this time the Atomic Energy
Commission
(now the Department
of Energy @oE)) and DoD
were tasked to do the preliminary
surveys and planning.
DoD was tasked to perform the cleanup itself, DoE to provide
radiological
support and certification,
and the Department
of Interior (DoI) to accomplish
rehabilitation
and resettlement.
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 In l?Y 1975 DoD requested a military construction
appropriation to accomplish the cleanup using civilian contractors.
Congress did not authorize this appropr~ation,
and instead
directed that project planning be revised to make use of
military personnel and equipment.
In the FY 1977 military construction
appropriation,
Congress provided $20 million to partially fund the cleanup,
stipulating that “all reasonable economies should be realized
in the accomplishment
of this project through the use of
military services’ construction
and support forces, their
subsistence, equipment, material,, supplies, and transportation which have been funded to support ongoing operations
of the military services and would be required for normal
operations of these forces.”
This direction from Congress required that DoD not
only manage the cleanup operation,
but that DoD personnel
actually perform the cleanup.
The Army, Navy, and Air Force
were accordingly tasked to provide personnel and equipment
to perform the various jobs required.
The Director, Defense
Nuclear Agencyr was appointed as the DoD Project Manager
for the cleanup itself.
Since your interest is primarily in the radiological
aspects of the cleanup, I might describe the Department
of Energy’s role in more detail.
The DoE is responsible
for providing technical support ‘to the DoD Project Manager,
for characterizing
and defining the radiological
environment,
for establishing
the criteria for cleanup levels, and for
certifying the radiological
condition of the Atoll after
the cleanup effort.
The cleanup portion of this program, managed by DoD,
consists of three separate efforts:
removal and lagoondumping of uncontaminated
debris and structures; removal
and crater-disposal
of radiologically
contaminated
debris
and structures; and excision and crater-disposal
of some
of the radiologically
contaminated
soil that remains on
the islands.
The radiological
contaminants
are described in detail
in AEC Report NVO-140, October 1973, attached.
The distribution of the”radiological
contaminants
is shown to be limited
roughly to the northern half of the islands of the Atoll.
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Typical total external”average
radiation exposure rates,
in the southern islands are less than one microroentgen
per hour.
The exposure rates for the northern islands are
higher, as one would expect from test history.
These levels
range from total external average exposure rates of 5 microroentgen per hour to around 100 microroentgen
per hour.
As a matter of interest, external exposure rates in the
United States from natural background ranges 6 to about
10 microroentgens
per hour.
The primary radioactive
isotopes are cesium-137,
cobaltand transuranic elements
(plutonium and
60, strontium-90,
americium) . The former isotopes are relatively
short-lived;
The primary
whereas the transuranic
elements are long-lived.
purpose of the radiological
soil cleanup is to reduce the
transuranic elements to levels that do not pose long–term
Of course,
hazards to the returning people of Enewetak.
in removing soil which contains transuranics,
any other
radioisotopes
present will also be r_emoved.
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Service personnel who have the potential
for being
exposed to radiation consist only of those who are actually
engaged in the removal and disposal of the contaminated
debris, structures,
and soil.
Typical duties involve operating bulldozers, backhoes, trucks, cranes, cement mixers,
and boats.
The attached Operation Plan will provide a basic
understanding
of the overall effort.
Of the 650 DoD personnel on the Atoll, possibly 400 have the potential for being
exposed to radiation.

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The overall philosophy
is for operations
to be conducted
in such a manner as to assure that radiation exposure to
individuals is limited to the lowest levels practicable.
The cleanup radiation exposure, standards are based on Title
10, Code of Federal Regulations,
Part 20, as implemented
in Department of Army Regulation
40-14, Control and Recording Procedures for Occupational
Exposure to Ionizing Radiation.
The limits for exposure in this regulation
are 5
rem per year, or 1 1/4 rem for any three consecutive
months.
The basic standard operating procedures
for the cleanup
radiation safety program were prepared by a group of experts
from DNA, DoE, Sandia Laboratoriesr
Los Alamos Scientific
Laboratory, and Lawrence Livermore Laboratory.
The program
“ is implemented in the field by a specially trained group
of Aix Force personnel organized into-Field Radiation Support
Teams.
These teams are under the supervision
of radiation
safety experts in the Radiation”Control
Division of the
Joint Task Group on the Atoll.
An on-site Radiation Control
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 Committee, which incluu”es a medical doctor, a DoE representative,
and a representative
from each of the Service elements,
monitors the overall radiation safety program.
In addition,
an independent audit and inspection team of experts headed
by the Directorr Armed Forces Radiobiology
Research Institute,
and including representatives
from DoE, the three Servicesf
and AFRRI visit the Atoll on a quarterly basis to ensure
the program is being properly implemented.
In order to assure compliance with these standards
and insure that any exposure is kept to a minimum, access
When
to the contaminated
islands is rigidly controlled.
personnel do work on these islands, it is under the supervision,
of the Radiation Control Committee, and under the constant
surveillance of a Field Radiation Support Team.
This team
monitors the local radiation environment,
continually
samples
the air for airborne activity, determines
the level of protective equipment needed, and monitors personnel for contamina~
tion.
Specific procedures have been formulated to provid?
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detailed day-to-day guidance on safety and other procedures
pertaining to operations
that might involve radiological
contamination
(copies attached).
Although the low gamma radiation levels found at Enewetak
Atoll would not normally require a full-scale dosimetry
program, we have chosen to establish one.
All personnel
who work on, or visit, the contaminated
northern islands
(the controlled islands) are issued a film badge on a monthly
basis.
Self-reading
ionization chambers
(pocket dosimeters)
are also issued, as required, to supplement the film badge
program, and are read on a daily basis.
Whenever earth-moving
operations are to be conducted
in contaminated areas, water sprinklers
are set up to minimize resuspension of contamination.
During transit the
trucks are wet-down and covered with tarpaulins for the
same reason.
Air samplers are set up immediately downwind
of the operation to monitor any airborne hazard.
Personnel
involved in earth-moving
operations wear respirators
and
protective clothing.
Urine samples are collected from personnel who have worked on the controlled
islands to monitor
for possible internal plutonium contamination.
The effectiveness
of this extremely conservative
approach
toward $ampling the radiological
environment
and controlling
exposure to it is borne out by actual radiological
exposure
data over the first year of operations.

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As far as exposure to external gamma radiation is cbncerned, our calculations
have shown that exposures should
not exceed 60-70 millirem per month.
To date, in the hundreds
of film badge readings takin, only 44 positive values have
been recorded, with the highest being 70 millirem, and only
4 (70, 70, 50, 42 millirem) exceeding 10% of the permissible
monthly exposure of 416 millirem.
As far as internal exposures, our intensive measurement
program has shown no evidence of any intake whatsoever.
In the thousands of hours of air sampler operation, no airborne radioactivity
above background has been detected.
NO indication of internal exposure has been detected in
analysis of face mask filters, and bioassay urine samples
on departing workers with a potential for exposure have
all been negative.
In regard to your suggestion that the Services might
want to consider using only volunteers
in the cleanup work,
this is being done insofar as practicable.
Except for a
few of the DoD personnel
(such as the Joint Task Group headquarters) , assignment
to the Atoll is for a 150- to 170day temporary duty period.
The few exceptions
are assigned
for a one-year tour.
Each Service handles its personnel
assignment slightly differently,
but in each case, every
o
effort is made to obtain volunteers.
Quite obviously it
would be impossible to man such an effort with the requisite
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skills, over the nearly three–year life of the project solely-”
with volunteers.
To date many, though certainly not all,
of the personnel engaged have been volunteers.
The participants
are fully apprised of the known and
potential radiological
risks involved in the operation.
Upon arrival, all personnel receive an initial orientation
covering the operation and the potential
hazards, not only
radioactive,
but also sunburn, coral, fish and others.
Those who axe to be engaged in cleanup of radioactive materials
undergo additional
training covering operations
in a controlled area and the risks expected.
Further, each Service
conducts its operations
under close leadership
and supervision, and in accordance with the pertinent
directives,
regulations,
and standard operating procedures.
As regards permanent
central computerized
data

records, DNA has established
a
base at Field Command in Albuquerque

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to record the pertinent data on all personnel involved i,n
the cleanup and, for those working with radioactive materials,
to record all exposures.
The data base includes a record
of operational
activities,
the type of work being done,
location, air sampler readings, radiation survey readings,
personnel dosimetry and urine sample results.
These records
will be stored permanently,
and a computer-based
ready–retrieval
system is being developed.
Other permanent records are being kept as well.
Prior
to arriving on the Atoll individuals
undergo pre-deployment
physical examinations
which pay special attention to past
history of exposure to ionizing radiation and baseline blood
“T
counts.
The results are entered in individual permanent medical records.
The monthly film badges from Enewetak
2/
are processed by Lexington Blue Grass Army Depot Activity,
k a<}
which maintains its own permanent record of the results,
R“
and sends a copy to the Joint Task Group Radiological
Pro- ‘qo~ ,
tection Officer for entry in individual medical records.~
~, Thus any exposure received by an individual while on the
Atoll will be entered in his own medical record as well
as into the DNA central data base.
Should exposures warrant,
whether recorded by dosimetry or shown by bioassay results,
follow-up examinations
and tests will be instituted.
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In summary, we are providing Every possible> protection
to personnel engaged in work with radioactive materials.
The protection is so extensive that audit and inspection
teams have repeatedly advised that the measures are overly
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protective, considering
the hazard invo~ved, and should
be reduced.
We are providing what is probably the most
complete record system ever established
for any operation
involving radioactive materials.
It has been, and will
continue to be, our objective to insure that personnel
exposures to radiation are limited to the lowest levels
practicable,
and that safety of personnel is the overriding
priority in the operation.
On behalf of the Secretary of Defense, and all of us
involved in the cleanup project, I would like to express
appreciation
for your interest and concern over the health
and safety aspects of this difficult but must important
mission.
I stand ready to brief you or year staff, or to
provide any additional-information
desired.
Sincerely,

Enclosures
“
See attached listing

R. R. MONR03Z
Vice Admiral.
Director

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ENCLOSURES

4

1.
U.S. Atomic Energy Commission Report NVO-140, VO1
Survey.
111, October 1973, the Enewetak Radiological

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FCDNA OPLAN
2.
Atoll, Marshall
3;

4.

600-77, 29 April
Islands.

1977,

Cleanup

of Enewetak

Standard Operating Procedures: Air Particulate
Sampling Proa. - 608-01, 21 Jul 77:
cedures
Debris Survey Procedures
b. 608-02.1, 3 Dec 77:
Decontamination
of Facilities
c. 608-03.1, 12 Dec 77:
and Equipment
Hot Line Procedures
d. 608-04, 5 Jul 77:
Respiratory
Protection
e. 608-05, 5 Jul 77:
Radioactive
Source Test Prof. 608-06,
12 Ott 77:
cedures
Source Accountability
and Con9* 608-07, 12 Ott 77:
trol Procedures
Radiological
Guidelines
for
h. 608-08, 9 Nov 77:
Ground Zero Operations
Radiation Dosimetry Records
i. 608-02, 21 Jul 77:
Bioassay Procedures
608-04,
20
July
77:
30
Enewetak
a.

Atoll

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Instructions

Radiological
Briefing for Arriving
.
Aug 77:
Enewetak
Access to Radiologically
Controlled
“
5702,
15 Aug 77:
Islands
Radiation Monitoring
of Blasting
5703, 18 Aug 77:
Operations
Radioactive
Source Test Procedures
.
5704, 29 Ott 77:
FRST Training
5705, 1 Feb 78:
Administration
of Personnel Dosimetry
5706,
29 Mar 78:
Program
Personnel Protection Levels
S707,
3 Apr 78:
5701,

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Persons,

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c.
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