The Human Plutonium Injection Experiments

The Human Plutonium Injection Exper-

Number 23  1995  Los Alamos Science  

205

District.

The Rochester Patients. Eleven pa-

tients (HP-1 through HP-11 in Table 2,

page 208) were injected with plutonium

at the Rochester site during a period

from October 1945 through July 1946.

The patients included seven men and

four women who ranged in age from 41

through 68, with the exception of one

18-year-old.  None of the patients were

chronic arthritics or carcinoma patients,

however, they had various afflictions,

ranging from a hormonal deficient dis-

ease (Addison’s) to alcoholism, that re-

quired hospitalization.  

In the undated (1947 or 1948) draft re-

port of Bassett and Langham, it was

stated:

Preference was given to those who

might reasonably gain from contin-

ued residence in the hospital for a

month or more.  Special treatments

and other therapy thought to be of

benefit to the patients were carried

out in the usual manner. . . . Pa-

tients with malignant disease were

. . . omitted from the group on the

grounds that their metabolism

might be affected in an unknown

manner. . . . As a rule, the subject

chosen was past 45 years of age

and suffering from a chronic disor-

der such that chance of survival for

ten years or more was improbable.

These last criteria, it was hoped, would

avoid “late radiation effects [such as

cancer]” and present the opportunity, in

some cases, to “obtain post mortem ma-

terial.”  There were exceptions to the

“rule”: three of the Rochester patients

were younger than 45 (18, 41, and 44),

although the 18-year-old was seriously

ill (Cushing’s syndrome) and only lived

another year and a half.

Ten of the 11 patients were cared for in

the special metabolic ward of Strong

Memorial Hospital in Rochester (the

eleventh was in the hospital but his

condition was so serious he was not

moved into the ward).  The control pe-

riod lasted about 10 days, during which

time the patient was instructed in the

quantitative collection of urine and fecal

samples and the necessary adjustments

were made to the ward routine and the

patient’s diet.  After the patient had

proven capable of cooperation, a series

of control urine and fecal samples were

collected and physical and laboratory

Estimating Effects of the Injection Dose

Several methods were used to estimate the potential effects of the amount of

plutonium being injected into the human subjects.  These methods were out-

lined in the various documents written at the time or published later in the

fifties, and here, we summarize two of these.

Acute toxicity. An accepted approach, especially for chemical toxicity, was

to determine the acute-toxic LD50 dose for animals (the amount that caused

death in 50 per cent of the animals) and then set the safe level for humans at

least 10 times lower.  Plutonium injections in rats showed (on the basis of mi-

crograms per kilogram of body weight): 700 to 1000 micrograms caused half

the animals to die in 30 days; 200 to 600 micrograms caused half to die in

150 days; and 10 micrograms caused no deaths after 420 days.  The “safe”

acute-toxicity dose would thus appear to be 20 to 60 micrograms per kilo-

gram of body weight (1500 to 4600 micrograms total for a 170-pound per-

son).  Using acute toxicity is most applicable for terminal cases, such as the

three Chicago patients (see Table 2, page 208).  The injection dose for CHI-1

was about 0.06 microgram per kilogram of body weight, more than a hundred

times lower than the observed no-effects dose in rats.  CHI-2 and CHI-3 were

each given the maximum injection dose of any patient in the various studies,

and this dose was about 2.5 micrograms per kilogram of body weight, still 4

times lower than the no-effects dose in rats and about 10 times lower than

the “safe” acute-toxicity dose.  The Chicago scientists were thus able to con-

clude in a report discussing CHI-1 and CHI-2 that “insofar as can be deter-

mined the clinical course in neither of the two cases was influenced by the in-

jection of plutonium.”  (Clinical data for CHI-3 were never documented.)

An alpha-emitter safe dose.  In a draft report authored by Bassett and Lang-

ham in 1947 or 1948, they stated that an accepted safe dose to irradiated tis-

sue for an alpha emitter was 0.01 rep per day (where 1 rep, a “roentgen

equivalent physical,” corresponds to the absorption of 93 ergs per gram of tis-

sue).  They felt that “a dose of this [size] appears to carry little likelihood of in-

jury to cells.”  Using the activity of plutonium-239 and the energy of its alpha

particles, they calculated that this dose corresponds to 32.6 micrograms of

plutonium if the plutonium is distributed uniformly throughout the body and 5.2

micrograms if the plutonium is concentrated in the skelton with a uniform dis-

tribution in bone.  “Unfortunately,” they wrote, “radioautographs reveal a far

from uniform distribution of plutonium in bone.”  Furthermore, “early localiza-

tion of a large fraction of the dose in the liver . . . is a distinct possibility.”

They estimated that, in the regions where the plutonium concentrated, a 5-mi-

crogram body burden could result in a dose to tissue that was ten times high-

er than the accepted safe dose of 0.01 rep per day.  Thus, they were aware

of the fact that a 5-microgram dose most likely exceeded accepted standards,

depending on the assumptions regarding distribution in the body.

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