The Human Plutonium Injection Experiments

gested that the initial low rate was most

likely due to “some metabolic abnor-

mality of the subject.”  Indeed, it was

noted that urine protein tests indicated

that HP-12’s kidney function “may not

have been completely normal at the

time of injection.”  Another explanation

was “the stability of the +4 citrate com-

plex”—50 per cent of the injected dose

was still circulating in the blood four

hours after injection.

One positive note was the fact that the

excretion rate seemed to have leveled

off after a couple of weeks at 0.02 per

cent, rather than the 0.01 per cent pre-

dicted from animal data.  If the true ex-

cretion rate in humans was twice as

high as the rate in animals, then earlier

urine assays from plutonium workers

that had been interpreted using the 0.01-

per-cent excretion rate had overestimat-

ed the body burden by a factor of two.

When HP-12 was operated on for re-

duction of the fracture in his knee,

biopsies for analysis were taken from

the kneecap and the top end of the

main bone in the lower leg (tibia) close

to the knee.  The intent of obtaining

those samples was to see how much

plutonium had been deposited on the

bone in the 96 hours since the injection.

At a later date, fifteen of his teeth were

removed (it was noted on his initial

physical that “patient had marked caries

and pyorrhea [an inflammation and dis-

charge of the gums]”), and these also

became available for plutonium analy-

sis.  Langham reported on the concen-

trations of plutonium in HP-12’s bone

and teeth in 1950; they were compara-

ble to the levels in tissue samples from

other subjects. 

Chicago. Sixteen days later on April

26, 1945, a second human plutonium

injection took place at Billings Hospital

in Chicago.  A sixty-eight-year-old

man, later identified as CHI-1, was in-

jected with 6.5 micrograms of plutoni-

um (0.4 microcuries) in the chemical

form of the +6 citrate salt.  This man

had an advanced case of metastasized

cancer of the chin and lungs and only

lived another 160 days.  An autospy

was performed after his death, and a se-

ries of tissue and bone samples were

taken so that the distribution of plutoni-

um in the body could be determined.  

The initial 24-hour urinary excretion

rate (2.5 per cent) for CHI-1 was much

larger than for HP-12 (0.1 per cent).

However, within a few days the rates

for the two subjects were comparable,

and after 21 days, the rate appeared to

level off—at about 0.03 per cent of the

injected dose.

One of the findings of these first two

human experiments was that the

amount of plutonium excreted in fecal

matter was considerably lower than in

animals (compared to some species, a

factor of as much as six times lower).

In fact, the human feces excretion rate

was comparable to or less than the

human urinary excretion rate, and so

analysis of human fecal matter did not

appear to be a more promising way to

determine plutonium body burdens, as

had been suggested by the animal ex-

periments.

California. On May 14, 1945, a third

person, CAL-1, was injected with plu-

tonium at the University of California

Hospital in San Francisco.  CAL-1 was

a 58-year-old house painter that had

been diagnosed with stomach cancer

and was thus expected to live only six

more months.  Surgery revealed a firm

tumor that extended into the liver and

the tail of the pancreas, confirming the

diagnosis of cancer, and a large part of

his stomach was removed.  However,

The Human Plutonium Injection Experiments

Number 23  1995  Los Alamos Science  

197

Several weeks after the first Chicago patient had been injected with plutoni-

um, the Met Lab sent to Los Alamos selected sets of aliquots of this patient’s

urine, including single small aliquots of the first and third voidings collected

the first day after the injection.  Later, they sent five 100-milliliter aliquots

from each of days 40 and 41.  When Los Alamos analyzed the two early

samples using their procedure, the values (59 and 0.45 picocuries per cubic

centimeter, respectively) agreed with those of the Met Lab (58 and 0.4 pic-

ocuries per cubic centimer, respectively).  Despite the fact the two labs used

different plutonium-extraction techniques, this agreement provided evidence

of comparable radiochemical proficiency and instrument calibration, at least

when the count rates were high (2935 and 31.0 counts per minute, respec-

tively).  (A similar comparison was not done with samples from Berkeley.)

The measurements for the ten aliquots from days 40 and 41 (with plutonium

concentrations of only about 0.01 per cent of the injected dose) were less

satisfactory.  The excretion values obtained at Los Alamos ranged from 0.00

to 0.03 per cent of the injected dose, which, although they bracketed the

Chicago results (0.011 and 0.009 per cent), were suspect because of the

large measurement error.  The uncertainty was due to a count rate for the

samples (1 to 2 counts per minute) comparable to the background rate of 1

count per minute.  This background was a result of the lanthanum-fluoride

co-precipitation step, which introduced alpha-emitting impurities.  The Chica-

go procedure did not use lanthanum fluoride, and their background was

lower, which allowed them to achieve significant results with 100-milliliter

aliquots.  Unfortunately, the Chicago procedure would reach the limit of 

 

its

detectability if the plutonium concentrations being measured were any lower

because of an inability to analyze large urine samples.

A Cross-Check of Analytical Procedures

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