Document Rj00Q9D5RJyeQRdgjXrMMJpxB

March 51 1950 Dr. H. W. Elley, Director, Technical Division, Organic Chemicals Department, E. I. Du Font de Nemours and Co., Wilmington 98, Delaware. Dear Doctor Elley* I think it time to report to you on the progress of the investi gation of the ultimate fate of inhaled lead which we are under taking under the partial financial sponsorship of your Company. The chamber has been erected and Mr. Roberts of our staff is engineering the accessory equipment, most of which is installed or available for installation. We had gone slowly and step-wise into the purchase and installation of equipment, since this type of situation has not been met before. One of the problems relates to the supply of particulate lead, which must be dealt with in a precise manner. Some weeks have been spent in creating a source of finely divided lead. I wish to introduce Into the chamber the nearest approximation to lead in the exhaust of automobiles, and at the same time to avoid the use of an internal combusti.on engine. It now appears that the combustion of tetraethyl lead in an air stream led through a gas burner will give us what we want in the form of lead oxide, without other undesirable constituents. The uniformity of the oxide, with respect to rate of production, particle size and physical form (amorphous or crystalline) is an important matter, and it appears that we shall be able to get what we require. Other methods suggest themselves for obtaining other lead compounds in other states of subdivision, but we shall not try to deal with these, at least for the purpose of the first experiment, if the present methods prove to be satisfactory. The problem of uniform mixing of lead-laden and uncontamirated air streams has apparently been solved satisfactorily, hut perhaps I am optimistic. The removal of the particulate lead from the effluent air can be handled by electrostatic precipitation (2 Precipitrons in series). The uniform distribution of the mixed air throughout the chamber can be accomplished without serious difficulty, we believe. The foregoing features of the experiment are the that provide the more serious difficulties in the establishment of adequately con trolled experimental conditions. I have not ignored these diffi culties previously, realizing that their adequate solution was the foundation of ^ work, but I have not made proper allowance for the time they would take, since Iwas thinking primarily of physiolo- K E 0003313 Dr. H. V, Elley - (2) - March 21, 1950 gical rather than engineering factors. Some further time vill he required to solve them completely. Meanwhile ve are not standing still. As a preliminary to the exposure of an experimental subject (or subjects) in the respiratory chamber, I had to find a suitable subject and make the basic observations on which the experimental work could be extended. One subject has been found and engaged. He will begin his work on the first of April. The completion of preliminary and control obser vations will require three to four months, arid by thattime' provi sion for the technique of exposure in the chamber will have been made.-: . , - . : - . v - v > v -This may all seem deliberate andindeed-slov of accomplishment , but it is necessary; to be sure as we go, since otherwise part of a costly: program Of experimentation will be wasteful oth perhaps even worthless .7.We cannot afford t o m a k e errors that will ruin' ths' suitability of a n experimental subject for iong-bema observations, ,since ,human subjects ifoir work of this type <to>- obtain ahd to keepr. MOreover ithis, work will -require'-^ars'tb cbme to' fruition, and- therefore there is no good reason*-for rushing into an inept beginning I have been ccmpelled to wait -foie several- years for the facilities with which- to begin this- wdlrk an$' I. have been ? irked by the delay. I want ho more lost time -than that which is unavoidably.associated with careful procedure.7 :i . ` k r r ; your -visit to the: Laboratory can be made at any mutually convenient tiiie you may choose from now on.. The nature of the experimental program can now be presented realistically*'despite the fact that the subject will not be exposed to abnormal quantities of lead in the air, and the actual methods of procedure, aside from certain final details of the operation of the chamber, can be discussed in some detail. Open dates,with the exception of Saturday, April 8, are not available until,Friday, April 14. I shall be here, however, on April 17, 18,: 19,'20 and 21 (having certain classes on these days, I am sure to make no plans for being out of town).- The week of April 22 is filled by an out-of-town meeting, but April 28 and May 1 and 2 are open. On the other band if you prefer to wait until the chamber is operating, 1*11 let you know about this later. Cordially yours, RAX ef Robert"A. "XeHoe,M'!>E. !<(' 0003314