Document 850QYM1peJzpYNNVMj0Rka8Md

February 2, 1955 Mr. M. L. Ernsberger Assistant Director Organic Chemicals Department E. I. Du Pont de Nemours and Company Wilmington 98, Delaware ` Dear Mr* E m s b e r g e r : Pursuant to our conversation of some days ago, I enclose herewith a brief memorandum giving you the status of the work on the inhalation of finely divided lead in the atmosphere. I have also sent a letter of Dr. Gehrmann, a copy of which is enclosed, on the other projected investigation which I mentioned to you. My secretary has acknowledged receipt of your Company's check for $5,000.00. The statement of the entire financial situation, as of December pi, 1952, will be forwarded as soon as it is available. It may be by the time this letter, being dictated on Saturday afternoon (January pi), is typed, but if not, it will follow later. There is another matter about which I raised a question previously with Dr. Kirkpatrick, which now has come up again. In discussing with Mr. Roberts the preliminary engineering of our third experiment, in which we hope to study the influence of the size of the particle (lead oxide, if feasible) on the respiratory retention and absorption of lead, it appears that we shall have considerable difficulty unless ve have more direct resort to an electron microscope than is now available. Other related problems, a s , for example, the size of the particles and the composition of lead in the atmosphere of the city, suggest our great need of such equipment. I've been postponing the purchase of such equipment because of the great cost of it. Actually, when I brought the matter up with Dr. Kirkpatrick the expenditure of not more than $5,000.00 toward the purchase of the equipment was authorized (his letter of May 7, 1951) This was not done, and I would not presume to take it for granted that the proffer of this share of the necessary sum (something under $20,000.00, I believe) is still in effect. We shall look into the matter of what can be done about this at once, and what it will cost, vithout making a definite commitment. Meanwhile, if you care to consider the matter with your associates and let me know t f j T 0003299 MEMORANDUM OH THE PROGRESS OF THE INVESTIGATION OF THE RESPONSE OF HUMAN SUBJECT'S TO THE INHALA TION OF LEAD IN THE ATMOSPHERE IN VARIOUS CONCENTRATIONS AND IN VARIOUS FORMS , WITH RESPECT TO PARTICLE SIZE Aim CHEMICAL COMPOUND 1. The experiments were initiated on April 21, 1950, when an experimental subject after certain preliminary examinations as to his physical fitness, began, day by day to collect samples of all food and beverages consumed (duplicates), all feces evacuated, and all urine voided These were analysed for their lead content, thus providing data on the daily intake and output of lead via these avenues. Additional observations were made at regular, frequent intervals, some daily, some weekly and some at longer intervals, to determine the subject 1y physiological status in a number of respects that might be pertinent later, during the test period. These observations were carried out under the normal conditions of daily life in the routine of the Laboratory and of the subject's heme, without there being any experimental inter ference with the incidental (normal) exposure to, or response to, lead, until January 13, 1951, at which time the subject was first introduced into the respiratory chamber which had been designed for the purpose of these experiments. No lead was introduced into the chamber at this time, the purpose being to accustom the subject to the routine of doing his daily clerical work in that environment. These observations ended January 19, 1951. 2. Having gathered the necessary preliminary data, the experiment,proper, began on January 20, 1951, when for the first time, the subject was exposed to lead in the atmosphere of the chamber. The exposure continued in this manner for approximately ? 1/2T hours pr 4a? en 5 day per week* with a fw brief period* of emission, corresponding to bat might occur lu relation to any occupational exposure to lead frets the date indicated above until December $4 1S52 * fl conditions of this apoeux* m m m follows* - the approximate concentration of lead in the air of the chamber was Q.075 mg* per otfela meter* the compound was lead oxide (the aequloxlde), and the mean else of the particles of lead oxide was about 0 .0 5 micron* Full data on. all of the- foregoing matters will be tabulated and reported fully in due course* The exposure was brought to an end at the date indicated* because it seemed to he evident beyond doubt.* that the subject had reached a state of substantial equilibrium with the conditions of the experiment* with respect to the levels of load concentration In his blood and urine* These bad been static for nearly a year* with due regard to the minor fluctut lone that are found to be characteristic of this state at different times and particularly at different seasons of the year* Indeed no such length of exposure would have been necessary to establish the fact of the equilibrium, had it not been for such minor fluctuation since the possibility of progressive trends had to be eliminated. All of the analytical and other data- of the foregoing observations are under study and will bo ready for reporting at an early date. Meanwhile* however* the Observations on this subject continue from day to day* with respect to the intake sad output of lead* so as to establish the extent to which the small quantity of lead which was retained in the body of the subject during the period of experimental exposure la eliminated subsequently-. *:he evidence as to when this process comes to an end can be found In the rate of ths urinary sxoratleii of lead* When this has returned to the prc-experlmental level this experiment td.ll have been completed * ' 5 . While the foregoing experixacnt was toder way, a second subject was c e a s e d cad pat through the preliminary observations necessary to the initiation of the next experiment. The detailed study of the normal iatalee and output of lead on the part of this subject (F.C.) began on January 22#.193* and continued until December 24, 193# at which time the subject was freed from the necessity of collecting soBplos of his food and excreta, in a brief respite before hie introduction Into the chamber for the- prolonged observation of the second major experi ment The chamber has been cleaned throughly, all of the accessory apparatus has been or is being checked, and the new set of experimental condition are being engineered, tested aad confirmed as to their reproducibility and. -stability, it is anti cipated that ev@ryt.Mng will be in readiness at a very early date to initiate the observations on Subject F.C. The conditions are to be essentially identical with those of experiment Bo. 1 # except that in concentration of lead in the air of the chamber is to be increased to 0*15 mg* of Fb, in too f o m of the seequi oxide, per cubic metes of air* It is anticipated that this experiment will not continue for more than a year, at the most, since the level of lead absorption* under the experimental conditions, is expected to reach a point near, but pointing (by extrapolation) toward* that which industrial experience ha taught us to regard as potentially hazardous* Obviously it will be terminated before the subject reaches the danger point, but not prematurely on the baele of the preconceptions which, cling teaooicusly around a standard prescribed yeans ago and on rule of ttassb evidence for safe iadusinlai praotlee* The crucial character of this exper&aeaiai examination of this standard requires that objective isfonsation he obtained by which the. standard cm be substantiated or vitiated 4. the extremely fortunate outcome of Experiment if. 1 with respect to the sisal! amount of lead retained by Subject P P makes It possible to engage tbia same subject in m subsequent experiment of separable type if he Is willing, to participate. Consequently the observation on this subject can be continued for a longer period than sight otherwise be necessary to establish his return to the base line from which experlaent Mo* 1 started* Meanwhile he is being trained further in certain of the technical operation of the Laboratory la order to occupy his time# to cultivate further his interest in the iterators' and to hold hiss in work that is compatible with his oastlnuatiofi aa an experlnestal subject From the Kettering Laboratory in the Department of Preventive Medicine and industrial Health# College of Medicine University of Cincinnati ' January 31# 1933 KE 0003303