were known when the first milligram samples of the
surgical rubber gloves and respirators (Wilson 750
material arrived at Los Alamos in the spring of 1944,
during all chemical procedures involving plutonium
However, to be aware of the potential biolog-
and (c) whenever possible, use of closed systems
ical hazards of plutonium and to protect against
(at first, homemade dryboxes with rubberized canva:
them were two entirely different matters.
sleeves attached to surgical gloves).
Safety
Sometimes
i-
regulations could be established on the basis of
was impractical to use a closed system, and chem-
experience in the radium dial paint plants, but
ical hoods had to be used (not made of stainless
Protection problems in the two cases differed by
steel in the early days).
Many orders of magnitude.
apprised of the hazards of plutonium (as they were
(Milligrams of radium in
All workers were fully
watch plants were subjected to simple mechanical
then known) and were required to sign a statement
operations, whereas at Los Alamos kilogram quanti-
saying they would abide by the safety rules.
With
ties of plutonium were involved in complex chemical
rare exceptions, the workers cooperated to the bes
and metallurgical manipulations.}
of their ability, although during the tension and
All work with
plutonium was carried out in the wooden Chemistry
feverish activity of developing the first atomic
and Metallurgy Building called "D Building" (see
weapons it was difficult to avoid some shortcuts i
Fig.
the observation and enforcement of safety rules.
1).
Stringent safety regulations put into
effect included (a) a complete change of street
clothing on entrance to the contaminated areas with
-When milligram quantities of plutonium first
became available to Los Alamos chemists and metal-
two changes per day of freshly laundered coveralls,
lurgists, efforts to live with what was considerec
canvas bootees, and surgical caps
(all persons
to be safe contamination levels were hampered by
showered on leaving the building);
(b) use of
the fact that portable alpha counters and continuous air samplers had not yet been developed.
“Tt is a matter of interest to modern day plutonium
workers that the air entering the D Building was
cleansed of dust by electrostatic precipitation
methods. However, air leaving the building was unfiltered for the most part, since few, if any, of
the exhausts even from plutonium-containing hoods
had filters.
Hor
ever, because of the urgency of the times, work
with plutonium had to proceed, and improvised
methods of monitoring and decontamination were unbelievably primitive by today's standards (see
Appendix A}.
Because stationary counters were the
only means of detecting alpha particles from plutc
nium, it was necessary to make "swipes" with
lightly oiled filter paper of the laboratory surfaces considered most likely to be contaminated
and to bring these paper strips to the alpha proportional counter for counting.
This was done
systematically on a daily basis (or after an accident) in each laboratory containing plutonium
{6 swipes per laboratory).
Any "swiped" area
(approximately 6 x 6 in.) having an activity of
more than 500 counts per minute required
aK
There was a semi-portable counter called Pluto
first available in March 1944, but it was very
een hl eiamea
ne
Fig. 1.
A ee ag
Sg
The original wooden D Building which housed
the chemists and metailurgists in CMR
Division. Note that the chemical hoods of
the laboratories on the first floor were
vented individually, usually without filtration.
bulky and its
limit of sensitivity was 5000 count
per minute. A more sensitive yet still cumbersom
counter called Supersnoop came into use in March
1945, but it was not until the instrument called
roppy became available in June 1945 that the monitoring situation really was under control.
Hance
counters were not available until October 1944,
when the first experimental models capable of
detecting 200 counts per minute were installed ir
the locker rooms.