The Human Plutonium Injection Experiments

 

180

 

Los Alamos Science Number 23  1995

physiological effects of ionizing radia-

tion was assembled under the direction

of Robert S. Stone.  The intention was

to develop health-protection methods

for workers involved in the production,

purification, and fabrication of uranium

and plutonium, including development

of ways to monitor personnel for expo-

sures to ionizing radiation by blood

tests.  In September, research was start-

ed to increase information about the

toxicity of uranium compounds.  

The chemical toxicity of uranium (its

radiological risk was unknown) was

identified with heavy-metal poisoning

related to deposits in the kidney and

bone.  Plutonium, on the other hand,

was an unknown health-risk factor.  If

plutonium metal or compounds were in-

haled or ingested, where would they de-

posit in the body?  What limits should

be set on internal body burdens that

would be safe?  What tests would indi-

 

L E G E N D

Manhattan Project Sites Involved with

Human Plutonium Injection Experiments

Animal studies

Analysis of plutonium injection experiments

Injection of patients with plutonium

.

.

Los Alamos

(Site Y)

First atomic bomb

Joseph Hamilton

Director of Berkeley

animal and human

plutonium studies

Louis Hempelmann

Director of Los

Alamos Health

Group

Wright Langham

Biochemist who

analyzed Oak

Ridge and

Rochester pluto-

nium experiments

Berkeley

Discovery of plutonium

Birth of nuclear medicine

Hanford

(Site W )

Plutonium production

reactors

The Human Plutonium Injection Experiments

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The Human Plutonium Injection Experiments

Number 23  1995  Los Alamos Science  

181

cate when these body-tolerance limits

were being approached?  As a result of

such concerns, efforts in health protec-

tion paralleled the growth of the nu-

clear weapons research (see “The Med-

ical Researchers”).

A contract was issued in October 1942

by the Met Lab to the University of

California Radiation Laboratory at

Berkeley to study the metabolism of

the radioactive materials that would re-

sult from the fission process in natural

uranium piles.  These studies, directed

by Joseph G. Hamilton, would initially

be limited to the metabolism in rats of

small quantities of cyclotron-produced

fission products (their radioactivity

would “trace” their course through the

body).  As larger quantities of the

transuranics became available from the

Clinton pilot reactor in 1944, the stud-

ies would focus on the assimilation,

distribution, retention, and excretion in

.

Chicago

(Met Lab)

Plutonium Project

First nuclear chain

reaction

.

Oak Ridge

(Site X)

Pilot reactor

for plutonium

production

Rochester

Rochester Medical

Project

Robert Stone

Director of Met Lab

Health Division

Stafford

 W arren

Medical Director of

the Manhattan Project

The development of atomic weapons by the Manhattan Project was

carried out during World War II at a number of universities and secret

laboratory sites across the country.  The icons represent facets of the

plutonium injection studies carried out at each site, including both ani-

mal studies (no background) and human studies (red circle in back-

ground).

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rats of neptunium, americium, plutoni-

um, as well as larger amounts of fission

products. 

When the Manhattan Project took over

direction of the weapon programs, it set

up its own Medical Office under the di-

rectorship of Stafford L. Warren, from

the University of Rochester, and this

office started medical, health physics,

and biological research sections at other

centers.  In April 1943, the University

of Rochester Project was authorized

based on the extensive experience of

the medical school there in conducting

biological studies with cyclotron-pro-

duced radioisotopes.  In contrast to the

Met Lab and Los Alamos, the

Rochester Project was not directly in-

volved with the design or production of

the atomic bombs.  It was responsible

for studying the biological effects of

various radioactive materials, using 

animals as the host.  Part of that work

included determining the comparative

toxicity of radium, polonium, and 

plutonium.

At this same time, it was agreed that

the Chicago effort would continue to be

responsible for the health programs it

already had underway, including the

recommendation of health safeguards

for other Manhattan Project sites such

as Los Alamos and the plants involved

with production of weapon materials.

The Met Lab’s Health Division contin-

ued its animal research, including the

radioactive tracer studies by Hamilton

at Berkeley and, by 1944, acute plutoni-

um toxicity studies at the Chicago site.

Each of the sites within the Manhattan

Project established their own group of

people to provide on-site health protec-

tion.  The Los Alamos Health Group

was created in March 1943 under the

direction of Louis H. Hempelmann and

began to plan for the health protection

of workers at Los Alamos.  Oppen-

heimer’s original intent was to rely on

other project sites for the development

of the health-protection methods.  How-

ever, by the summer of 1944, Hempel-

mann and Oppenheimer found they

could not always get the health-protec-

tion information they felt was needed,

and the Laboratory extended its activi-

ties, gradually taking on a role compa-

rable to other sites for health-protection

research and development on the haz-

ards of plutonium.

The heads of the various health divi-

sions—Stafford Warren for the Manhat-

tan Project at Oak Ridge, Robert Stone

at Chicago, Joseph Hamilton in Califor-

nia, and Louis Hempelmann at Los

Alamos—were destined to play a major

role in the decision to obtain plutonium

metabolic data from humans (see “The

Medical Researchers”).  All four were

medical doctors with strong back-

grounds in radiology, and in 1941,

three of them—Stone, Hamilton, and

Hempelmann—were working at the Ra-

diation Laboratory at Berkeley.  They

were thus knowledgeable about radia-

tion and its biological effects, including

research that involved the administra-

tion of small quantities of radioactive

materials into humans for biomedical

purposes.  

By 1942, Stone had gone to the Met

Lab in Chicago as head of the Health

Division, and Hempelmann had moved

back to Washington University in St.

Louis (where he had received his med-

ical training).  There he was responsible

for programmatic uses of that universi-

ty’s cyclotron.  By the summer of 1942,

both Hempelmann and Hamilton, the

latter responsible for operations at

Berkeley’s cyclotron, were caught up in

demands related to the war effort.  One

of their main responsibilities became

the production of plutonium by bom-

barding hundreds of pounds of uranium

nitrate to produce microgram quantities

of plutonium-239.  The irradiated urani-

um from St. Louis was sent to the Plu-

tonium Project’s laboratories in Chica-

go where Seaborg’s group was learning

how to chemically isolate the plutonium

from the uranium and the highly ra-

dioactive fission products.  The urani-

um irradiated at Berkeley was

processed at the Radiation Laboratory

under the direction of Art Wahl and

Joseph Kennedy, and much of that ma-

terial eventually went to Los Alamos.

The Berkeley and St. Louis groups each

produced about a milligram (a thousand

micrograms) of plutonium-239 before

January 1944, when the first gram

amounts of reactor-produced plutonium

started becoming available from the

Clinton site.

 

The Los Alamos Health Group. Op-

penheimer, at the recommendation of

John Lawrence at Berkeley’s Radiation

Lab, asked Hempelmann to head up the

Health Group at Los Alamos in March

1943.  Before coming to Los Alamos,

Hempelmann visited the Met Lab in

Chicago and discussed plans for the or-

ganization of the new Health Group.  It

was the opinion of the Chicago people

that changes in blood counts, such as

increased numbers of white blood cells,

would be the most sensitive indicator of

significant radiation exposures.  If he

was to be the “hematologist-in-chief” at

Los Alamos, Hempelmann wanted to

learn as much as he could about this

subject from Stone and others.  

While in Chicago, Hempelmann also

met with John Manley, who was re-

sponsible for planning for the Los

Alamos Laboratory.  Manley told him

that about fifty to sixty men might be

exposed to radiation hazards at Los

Alamos and he did not anticipate the

hazards being greater than those associ-

ated with supervoltage machines, such

as cyclotrons.  At that time, the Chica-

go Met Lab was responsible for pluto-

nium research, and Los Alamos was re-

sponsible for weapon design.  As a

result, Manley did not envision an ex-

tensive research effort at Los Alamos

using plutonium.  It would not be long

before that would change.

Worries About the Health

Hazards of Plutonium

Originally, it was intended that mil-

ligram amounts of plutonium would be

The Human Plutonium Injection Experiments

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Los Alamos Science Number 23  1995

continued on page 184

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