Attachment 13

Letter dated January 10, 1951 from Marion W. Boyer, General
Manager, AEC, to Robert LeBaron, Chairman, Military Liaison
Committee.


                           ATOMIC ENERGY COMMISSION
                             Washington 25, D.C.
                                                          COPY

BAW 10/3                                           January 10 1951

Honorable Robert LeBaron
Chairman, Military Liaison Committee
P. O. Box 1814
Washington 25, D. C.

Dear Mr. LeBaron:

As you know, one of the important problems that would confront us
in the event of a war in which nuclear weapons were employed
would be the amount of external radiation from radioactive
materials that military personnel could tolerate and still
effectively carry out their assigned duties and missions in the
Armed Forces. This problem was a principal subject of discussion
at the November 10, 1950 meeting of the Atomic Energy
Commission's Advisory Committee for Biology and Medicine. In
attendance at this meeting were Rear Admiral F. C. Greaves and
Captain C. F. Behrens of the Bureau of Medicine and Surgery,
Brigadier General William H. Powell, Jr., of the Office of the
Surgeon General, Air Force, and Brigadier General James P.
Cooney, Army Medical Corps, and Chief of the Radiology Branch,
Division of Military Application, Atomic Energy Commission. It
was suggested at this meeting that it would be helpful to the
Armed Forces to have the opinions of an ad hoc commission,
composed of physicians and radiologists whose recommendations
would be recognized as authoritative, to advise the Armed
Services of the permissible levels of radiation to which troops
could be exposed and still be expected to be effective as
fighting forces.

In order to obtain an accurate and authoritative answer to the
question raised at the meeting, the Division of Biology and
Medicine of the Atomic Energy Commission has consulted with a
group of the physicians and scientists of this country whose
experience in this field has been broadest and most extensive,
and whose reputation for clear thinking and good judgment renders
their advice and opinions of very great value. This group
includes clinicians and radiologists experienced in the use of
X-ray and radium in the treatment of human patients and who have
had occasion to radiate the human body in such treatments; it
includes physicians and scientists who were in Japan at the close
of the last war and carefully studied bomb victims at Hiroshima
and Nagasaki, the physician who treated the victims of the three
accidents involving acute radiation injury in the history of the
Manhattan Project and the Atomic Energy Commission; scientists
who have conducted and are well acquainted with the results of
experiments on the effects of radiation on various species of
experimental animals, including the genetic effects of radiation;
and physicians who were members of the Medical Board of Review
which appraised the medical work of the Manhattan Engineering
District.

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On December 8 these men met as a group in Washington at the
request of the Atomic Energy Commission. Attending and taking
part in this meeting were:

Dr. Alan Gregg, Director of the Division of Medical Sciences
Rockefeller Foundation, and Chairman of the AEC Advisory
Committee for Biology and Medicine, who acted as chairman of this
meeting.

Dr. Austin M. Brues, Associate Professor of Medicine, University
of Chicago Medical School, and Senior Biologist and Director of
the Division of Biological and Medical Research, Argonne National
Laboratory of the AEC.

Dr. Simeon T. Cantril, Radiologist with the Tumor Institute of
the Swedish Hospital, Seattle, Washington, Consultant to the
Atomic Energy Commission and to General Electric Company in their
operation at Hanford Works during the last war full time with the
Manhattan Project.

Dr. Andrew H. Dowdy, Professor of Radiology and Chairman of the
Department, Medical School of the University of California at Los
Angeles, formerly Professor of Radiology at the University of
Rochester Medical School and head of the Atomic Energy Commission
research laboratories located there.

Dr. Louis H. Hempelmann, Associate Professor of Radiology at the
University of Rochester Medical School, Special Assistant to the
Director of the Division of Biology and Medicine of the AEC,
formerly head of the Health Division, Los Alamos Scientific
Laboratory.

Dr. Robert F. Loeb, Bard Professor of Medicine, College of
Physicians and Surgeons, Columbia University. Specialist in
Pathology and Internal Medicine, Chairman, Medical Board of
Review, Atomic Energy Commission, 1947.

Dr. Curt Stern, Geneticist and Professor of Zoology, University
of California, member of AEC Advisory Committee for Biology and
Medicine, formerly Chairman of Division of Biological Sciences,
University of Rochester, and geneticist with the AEC Atomic
Energy Project located there.

Dr. Shields Warren, Professor of Pathology, Harvard University
Medical School, Division of Biology and Medicine, Atomic Energy
Commission.

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Brigadier General James P. Cooney for the Army, Admiral Thomas C.
Anderson and Dr. Robert Flynn for the National Security Resources
Board, and Major Gerrit L. Hekhuis for the Air Force.

The last-mentioned group attended this meeting for the purpose of
presenting to the group in further detail the problems in this
field already raised by the armed forces and to obtain personally
the conclusions and recommendations of this committee on the
subjects of importance to the armed forces and civilian defense
agencies.

Members of the Division of Biology and Medicine of the AEC acted
as staff to this committee in collecting and summarizing
pertinent available research data and clinical information and
presenting it to the committee for their consideration.

As a supplement to information gained personally by armed force
and civilian defense representatives at this meeting, the
Committee has asked me to write this letter summarizing their
views on the pertinent questions asked them.

This letter was submitted to each of them for any suggestions or
corrections they cared to make, and I can now tell you that the
members of this committee were in unanimous agreement that what
follows is a correct summary of their joint conclusions.

Question 1: Assume that troops are acutely exposed to penetrating
ionizing radiation (gamma rays). At what dosage level will they
become ineffective as troops?

Answer of the Committee: Uniform dosage of 50r to a group of
armed force personnel will not appreciably affect their
efficiency as a fighting unit.

Uniform acute dosage of 100r will produce in occasional
individuals nausea and vomiting, but not to an extent that will
render armed force personnel at any time ineffective as fighting
units. Troops receiving an acute radiation dose of 100r and above
ought to be given, as soon as feasible (within a week, if
possible), a period for rest and individual evaluation.

Uniform acute dosage approximately 150r or greater can be
expected rapidly (in a few hours) to render armed force personnel
as a group ineffective as troops through a substantial incidence
of nausea, vomiting, weakness and prostration. Mortality produced
by an acute dose of 150r will be very low and eventual recovery
of physical fitness usually may be expected.

Field officers should therefore assume that if substantial
numbers of their men receive acute radiation doses substantially
above 100r, there is grave risk that their commands will rapidly
become ineffective as fighting units.

Question 2: What dosage will render an air crew inefficient, that
is, unable to complete a mission, during a flight of one to three
hours, four to twelve hours, twelve to forty-eight hours?

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Answer of the Committee: In all three cases if radiation dosage
to flight crew members is held below 75r, radiation exposure will
be unimportant in determining the success or failure of a mission
provided the crew members had not previously received an
appreciable amount of radiation. In all three cases radiation
doses substantially above 75r, combined with human stresses
associated with military aviation missions in wartime, are
considered to very seriously reduce the odds for successful
completion of a mission.

Question 3: How often may an aircraft crew accept an exposure of
25r per mission and still be a reasonable risk for subsequent
missions?

Answer of the Committee: It is probable that at least eight
missions can be carried out at weekly or longer intervals, with
exposure of 25r per mission, before the chance of mission failure
becomes large due either to illness during the mission or
significant general deterioration in health and ability. More
missions may be feasible, but personnel should be carefully
checked and evaluated before each mission and particularly before
a decision to permit greater exposure than 200r total in these
divided doses is made.

The possibility should not be ignored that cumulative radiation
doses to the entire body above 200r may substantially reduce the
life expectancy of the irradiated individual.

Question 4: A submarine crew are receiving 25r per mission. How
many missions should they be allowed to make?

Answer of the Committee: The answer is substantially the same as
to question 3. It is probable that at least eight missions can be
carried out. Personnel ought to be carefully checked and
evaluated after each mission. The possibility of substantial
reduction in life expectancy by radiation doses totaling over
200r should not be ignored.

As indicated earlier, in arriving at these conclusions the
Committee took into account the results of extensive animal
experiments, the response of patients treated for disease by
X-ray and radium, observations on the effect of radiations from
the atom bomb detonated over the Japanese cities of Hiroshima and
Nagasaki, and accidental radiation exposures within the Manhattan
Project and the Atomic Energy Commission.

I believe you can accept these values as realistic appraisals
that can be used in planning with the convictions that their
predictions will be closely fulfilled in practice.

We are sending copies of this letter to the Chief of the Bureau
of Medicine and Surgery, Department of the Navy, and the Surgeons
General of the Army and Air Force.

Sincerely yours,

Marion W. Boyer
General Manager


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