Document NEoBEeR0zoQX1YNo81m2GrQvD
October 2 2 1949
D r . J . R. Albrecht, Plant Physician,
AutoLite Battery Corporation# Vincennes, Indiana.
Dear Doctor Albrecht:
I shall undertake to ansver the questions in your letter of
October 14 as veil as I can. First, let me say, hovever, that I
am not primarily responsible for the standard vith respect to the lead
content of the air of workrooms, although I know the background of
the standard quite veil indeed. The standard is, more or less, a
rule-of-thumb, which applies to dust more than to fume. It is
generally recognized among industrial hygienists that the potential
hazards of occupational exposure to lead vary greatly vith the
solubility and state of supervision of the lead particles in the
atmosphere. The standard is concerned vith highly efficient methods
of collecting the lead from the atmosphere, and therefore it is
based on the use of the electrostatic precipitator when dealing vith
fume and the use of the implnger apparatus when dealing with indus
trial dust. In general, it is fair to say that certain highly
insoluble dusts are lov in their toxicity, and that finely divided
fume is relatively high in toxicity. Fundamentally, however, this
relates only to the extent of the.absorption of the lead compound
and not to any essential, difference in toxicity otherwise. In
any case, the standard which has been developed is recognized as
inadequate to meet all situations, and therefore it is intended to
apply to the more dangerous for^as of lead in the atmosphere . 1
repeat, hovever, that it is based on a highly efficient method of
collecting the lead compound, and it fully recognizes that the
smallest particles are the most dangerous.
.
Actually, if you want my opinion, which is based on our own
observations and those of others, this standard is not low enough,
if one is dealing with lead fume. The latter is readily, absorbed
from the pulmonary tissue, and to the best of my knowledge and
belief, men exposed continuously (that is, every working day) to
concentrations of this order of magnitude will absorb quantities
of lead which will become dangerous after two or three years of
employment. For our own purposes in the tetraethyl lead industry
we do not regard the conditions as satisfactory if the lead concen
tration is in excess of 0.75
of lead per 10 cubic meters of air.
Even so, we keep careful and continual watch on exposed personnel
both by clinical means and by the analysis of blood and urine, since,
in our experience, this is the only means by which we can remove
men from exposure in time to avoid episodes of illness.
I mighf conclude this discussion by saying that, at present, no
Dr, J. R. Albrecht * (2) - October 22, 1949
Informed person would undertake to measure lead fume in the atmosphere by the impinger method. Even with-.the electrostatic precipitator one has to be very careful to maintain a very high voltage (around 14,000), or the electrostatic field will not act with suitable efficiency. The equipment, therefore, has to be maintained in excellent condition and tested critically in this respect at frequent intervals.
Sincerely yours,
RAK ef
Robert A. Kehoe, M. D.
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