Document 5X5zGXwv7yyvr4rznxwy4OmN

only 2.6, 19.5^ Dr# I", chart E. Eckardt, Director Medical faooureh .-'vision Esso Research and Engineering Company r*0. "OX 121 Llnoon, few Jersey Dear I'oct or Eckardtt Titr.o has had wings sine I received your letter of .Tr-no 6th, on coming the organic lead compound triraethylethyl load, for I have boon trying to clear a-ay a mountain of unfinished work including corros gondenco, co as to get away for a vacation# dew that hno and hoy;alike, have flown, with the exception of a few days of tho latter, I fool that I must not wait longer to find a suitable date, for a meeting v; it a -;on, but louat writ to you instead# Otherwise, I shall bo responsible for an undue delay in dealing with this natter# I an sorry now that I did not writ to you about this promptly# Since cur initial conversation, I have conrraliod a fox? responsible persona in Ethyl Corporation, and I an in position to givo you the essential toxicological information and to express my views on tho problem of tho uso of this material# 1 had no reservation at any tirto in .famishing yeu with the toxicological facts, but I could hardly telle to you Itheut considering with you tlxo hygienic aspects of the entire situation# I hesitated to go into the latter without consulting my associates in Ethyl Corporation, since as Ethyl13 Medical Director I could rot, in such a matter, fail to apeak to come extent for the Corporation# An -t is, I tin Informing hr# Scales of tho Detroit Laboratory and hr# burdock of the Sales Department, by confidential copies cf this letter, of what I nay, sine I must bo sura that there is no ambi-yiity in ryr words or moaning# First, v/ltn reference to the essential facts on tlxo. toxic clerical behavior of trimethylethyl lead: CD Tiiin compound, somewhat nor dense than tetraethyl load, and in round numbers about ton times as volatile, has much tho am toxicity and nod cf action as does tetraethyl lead, being slightly none toxic when drainiatrod by mouth, considerably loss toxic (apparently loss readily absorbed) when applied upon the shin, and somewhat more toxic (gram for gram of pb) vrhan inhaled as a vapor# Th concentration of those compounds In air, which io lot: al for rabbits exposed thereto for one hour, is of the order of to 5 ur# oxpressod as fb por liter of air# CONFIDENTIAL DP. Robert S* Sclcardt - (2) - <?aly .?(>, 19^6 (2) T",o foregoing minor differences In the toxicity of -hog o two cosrpotirds have little 'practical significance in promoting any real differences In trio long-term hazards of occupational xqosuro to thorn, since the fact of their absorption through tho akin and nffcor inhalation is tho really Important eonslderat3on, v'ndor those circ'rnstanees the hasard deponds as much upon tho turntion of tho exposure as upon its severity. (3) The distribution of this compound within the tissues of animals to which it has been administered, both initially and subsequently. Is of tho same typo as that of tetraethyl load, as judged not by any considerable number of direct observations made on the behavior of trimethylcthy!'load, but rather from a comparison.of the behavior of tetraethyl and totraiaothyl lead, those two compounds, only, having boon investigated extensively* Second, the potential hazard created by the substitution of trl;.-ofchylethyl for tetraethyl lead must be considered In two relationships: I. Tho hazards of manufacture Quito apart from tho problem which may be presented by tho creator chemical instability of trimthylothy1 load as compared with tetraethyl load (this is assumed to bo tho.case, and while the 5nfcmotion, available to me on thin -ratter Is inadequate, it is a problem to bo reckoned with serio-nsly from the hygienic aspect), she real problem lies In tlio greater volatility of this load eoypc-iud as compared with that of tetraethyl load. Tho lack of an appreciable Incidence of tetraethyl load poisoning in association with the manufacture of tetraethyl land as it has boon carried cut by carefully trained, highly capable and well supervised people In the r.S.A*, treat Britain raid Franc (and earlier in Germany) should not delude anyone Into t-ho belief that this is not a highly dangerous manufacturing industry* Something near to perfect performance in the arts of production is required to maintain those operations in safety, whilo tho r.cdical and hygienic regimen required to secure and portray tho safety of tho manufacturing personnel is cno of the most intensive. .and sustained efforts that la known to industry outside of the area of atomic energy* It is difficult to anticipate all of tho problems that would ho presented by a several-fold increase In tho volatility of the product to be uarmfactuned* Thor is little doubt that the difficulties could bo overcome in the manufacturing operations, but a stop-wlso development? of the process,a relatively small scale, would be necessary to tho achievement -of safo methods of manufacturo* It would be utterly foolhardy'to hako uso of the present manufaetaring facilities for tho Iqrgo-scalo manufacture of trimethylothyl lead. K & 0020506 CONFIDENTIAL Dr*. Hcborfc 11* dckardt - (3) - July 26, 1956 Ii# The hazards of the distribution and '.iso of tko product Too commercial distribution of gasoline containing tetraethyl loadwi&in the proscribed limits of concentration las boon shown to bo "a.fo from the aspect of the exposure of gasoline handlers to totraotkyl load (excluding the special problem cf tank cleaning) The factors responsible .for this safety, as doror.a trated ox?rijnonfcally prior to the extorsive use of leaded gasoline^and coni'irrod by experience, are those of (1) the dilution of tetraethyl load by gasoline to such an extent that its absorption through the skin is hindered to the practical vanishing point? and (2) the suppression of a significant amount cf vaporisation cf tetra ethyl load from, gasoline h?/1containers by its dilation in a solvent (gasoline) of relatively high vapor pressure (the application of Fault*s Law to this system foretells the facts demonstrated by orreorinorit) * It thus happens that hundreds of thousands of people `r t:y> petroleum industry handle present-day loaded gasoline without at sorb ing a practically significant quantity of load* they do, hov.'ovor, absorb sore lead, t?> quantity being Insiynlfleant as cor-varod with other sources, while the total lord cf absorption is Insufficient to result in a measurable accumulation in the body hi a 7ifotimo# Tko margin of safety in the above situation 7 s ayvrcciable V't d5fficult to .measure# I cannot cent isolate the effect of a ton-fold increase in tho volatility of the lead compound. in emnercial gasoline without great concern., for cesnlta an anticipatory approach to this problem by experimental verms, the f5nal test cf the safety of tho procedure will have to bo that cf practical experience* It is ny considered opinion that it would :-o unwise to Incur the risk of experience in cstablisking tho facts in thin natter# hot only would this bo costly in terms of experimental work of various kinds, but it ray well turn o'at to be unsafe, Hack-tracking would be a difficult and costly procedure, especially from the aspect of public uad erst muling# I trust that this will serve to convoy both tho. facta, which are very simple, and ny opinions, which, 1 hope, arc equally simple to follow# If 1 raise questions that require further examination I shall bo glad to discusa thorn with you# 8 Inc ere ly 'yours, 71AK: vr co - Ur# K K# Scales hr. b. ?, burdock }%Vorr nY'bfmmo,* '.fuT K 0020507