Document Gmkyx8rpXgvLdzJ5D6wB86b0r

April 21, 193Jl Dr, R* K* Sayers Bureau of Mines Dept* of Commerce Yfashington, D*G, - Dear Dr* Sayer3: X have had a conversation with Dr* Edgar in which he passed on to me your request that X give you my opinion with regard to the possibilities for danger associated with the distribution and handling of gasoline, containing up to 1|*5 oc* of tetraethyl lead per gallon, with the understanding that such gasoline 13 to be limited to aeronautical usage* I am glad to state my point of view and to present the evidence on which It Is based* Th possibilities for danger may be classified under the following headings} . (1) those associated with exposure to the prepared gasoline, including skin contact, inhalation of vapors of gasoline under all the conditions of use and spillage} and . (2) those associated with exposure to exhaust gases containing finely divided lead, on the part of pilots, passengers and the general public* It seems quite clear to me that we need not concern ourselves with the question suggested under the second heading since the opportunities for exposure to insufficiently diluted exhaust gases in confined or unventilated areas will bo insignificant in the case of aeroplanes as compared to those which have been afforded by automobiles without evidence of human lead accumulation, therefore there remains only the question of exposure to gasoline containing concentrations of tetraethyl lead up to 1 part in 84Q of gasoline# It is apparent that the vapors rising from tanks or open containers will show slightly Increasing amounts of lead, with increasing concentrations of lead In the gasoline* The vaporised lead in the atmosphere as the result of spillage will also be grantor for a given amount of gasoline, with every increase In the concentration of lead In the gaaol'ne* However, the amount of lead which will bo present In vapors above tanks are too small to b8 ~a Dr* R* H* layers of practical Importane, at the specified concentrations. Moreover, the problem of spillage, with complete evaporation of gasoline and lead is not likely to b of c;nsequence, since the gross amounts of gasoline handled at one place will be relatively small, and since spillage m a t be guarded against in any case because of fire hasards. In view of the complete lack of evidence that lead absorption has occurred from the inhalation of vapors of automobile gasoline under the conditions which exist In garages and filling stations, I cannot conceive of difficulty from a slight increase in the lead concentration of th small fraction of gasoline which is handled under the conditions which exist at air ports* The on factor which must be considered seriously is the influence of lead concentration in gasoline upon the 2'afce of load absorption through the skin of exposed persons. It 1ms been observed that lead is absorbed rapidly out of gasoline through the extent of 10 the skin of % by volume animals when In gasoline, iAtbsiosrpptrieosnent13to very much retarded when the concentration of lead is 1% in gasoline, and it fails to occur when the concentration is The available data do not justify the plotting of a curve from which the aero point of absorption might be predicted, but the magnitude of the change in absorption wmcheainktcrh3atrfieoosrnualtthsweelfplrroomabbaobtviheelid0try*o1p^t.hfartoI tmabd1so0oe$rspttniooot1n>,acpcepoasenecaserntatrthaattcioonIn-t would be hazardous, therefore, from th point of view of akin absorption to handle centrations approximating g1aspoalritneinco8In5.tOapianritnsg lead in con of gasoline. Evidence obtained from the periodic examinations of several msn at Wright Field who handled gasoline containing 6 ec. of TbiEfc)* per gallon toads to substantiate the foregoing conclusion* An Interpretation of the variation in the analytical results on these man cannot bo made with accuracy because they were exposed to Ethyl Fluid in the preparation of the gasolines which were being txsad for experimental purposes Suffice it to say, therefore, that the examinations of five men from time to time over a period of three years, during which they war regularly.axposod (by inhalation) to Ethyl Fluid, and to gasoline containing b cc* of Pb(Kfc)* per gallon did not result in any symptoms or signs of lead Intoxication or evidences of lead absorption* On th last examination of thoir excreta (19;>2) after throe years exposure, the following results were obtained. 0009230 - 3- Subject M.F.C# T.N.L* ff.Z. P*S. i?*K* E*RL* Pb in Faeces Hpi8(/Gra*ABh 0*05 0.05 0 *0i|. 0.10 0.08 0*01. ' Pb in Urine Mgs/hiter 0.08 0.08 0. 05 0.09 0. 05 ; 0.07 The above figures do not demonstrate the occurrence of significant lead absorption taking Into account the information now available on the wholo subject of lead exposure in relation to leaded gasoline* together with the foregoing observations* which are admittedly meager* I am convinced that the use of lead in aviation field up to ce* per gallon will not be attended by an increased hazard to any group of individuals* Vary truly yours, UK jig Robert A* Kehoe, K E 0009231