Document NGk37NKkKJrp2XD4dmxwkpX2R

December 27, 1944 19 D r . Charles H . Er ay , Eclipse Machine Division Bendix Aircraft. Company, Elmira , New York . Dear Dr. E r v & y I am sending you herewith a memorandum which covers the results of my observations at the time I visited your plant, togetherwith certain recommendations and some suggestions also with respect to methods of procedure. I trust that this will be cf use to you and your- associates, but if there is anything, further that I can do, please ci not hesitate to call upon me. F o r the sake of my own convenience in avoiding records and bookkeeping I am sending you also an account of my expenses plus a fee for my services. The low traveling expense is occasioned by the fact, that I was in Buffalo on other business . I trust that this will all be satisfactory. I shall be very much interested in knowing the results of any observations that are made and also of the practical conclu sions that are worked out in preparation for your enlarged operations. I 3hould also be glad to know the impressions that resulted from'the visit of some of your people to Vright Aeronautical. I enjoyed very much making your acquaintance, and it vas a pleasure to meet and discuss the situation with you and your associates. I trust we shall have the opportunity of meeting again. Sincerely yours, ivAK ef Enc. hooert A. Kehoe, M. B. K f 0005236 Bobert A. Kehoe, K. D. College of Medicine Eden Avenue Cincinnati 19, Ohio December C i 9 I t M rclipse Machine Division, Bendisi Aircraft. Company, Ilmira, Kev York. At tention ? Dr. Charles II. Ili^ay Fee in connection vith visit to plant on F r i d a y , Becember 15, including report traveling Expense 1 . 1 .j j . j u *7 ` X f 0005237 N7289.01 Expenses in connection with trip to Elmira, New York, Dec. 15, 1944 H. T\. (coach)Buffalo to Elmira and return Hotel - 1 night Meals Taxi, etc. Incidentals Total $7*15 4.00 j?.00 1 .85 1.33 $17*51 KE 0005238 N7289.02 MEMO ANBUM OK Vlf-XT TO 1CLIPH-. MACHIKF DIVir-IOE Kew'T O T This plent vas visited on December 15# 1 9 ^ for the purpose of examining Into the toxic hazards of exposure to the ingredients of high octane gasoline (lou octane aviation; on the part of men engaged in testing the performance of fuel distri buting pumps for aircraft motors, ihe present temporary facili ties for this work were examined and the performance of the work was observed. Afterward in a conference the means of protecting workmen in a projected building designed for this work, were considered Hazards and 'heir- Control (in principle ) The hazards of fire and explosion were not the subject of consideration but were merely mentioned in passing in connection with the employment of local exhaust, ventilation for the removal of gasoline vapors. The possibility of the carriage of explosive mixtures in air through ducts and motorized fans vas referred to as b special problem requiring expert engineering experience as to the means of avoiding: static c-lectrical accumulation especially in cold weather, end preventing ignition of vapors by operating electrical equipment. The toxic hazards that must be dealt with are those assoclated with the vapors of mixed hydrocarbons and of tetraethyl lead. Both of these may reach significant proportions, and therefore the conditions which influence their magnitude must be understood. Toxic Exposure to Hydrocarbons The toxicity of modern aircraft engine fuels is considerably higher than that of motor fuels commonly in use some years ago, the latter having been composed chiefly of the products of simple distillation of petroleum. Modern cracking, alkylating and re forming processes x*esult in the presence in aircraft fuels (and in other high compression motor fuelsj of various hydrocarbons of much greater toxicity than those produced by simple distillation. The situation may be illustrated by the fact that the tolerable concentration of naphtha or ordinary gasoline distillates in air for prolonged human exposure is generally accepted as approxi mating Ibbd p.p.m. by volume/while that of certain aromatic hydro carbons commonly found in lb., octane gasoline (up to IP to It rer cent by volumej is not greater than p.p.m. by volume. Moreover the irritating effect of skin contact vith the high octane gasoline is greater than that of commercial gasolines generally available in an earlier period The result of these facts is that much greater care must be taken to control the spillage and vaporization of 10 j octane gasoline and to avoid skin contact tiierevith, than would have been required to produce an equivalent degree of safety in the handling of ordinary motor fuels ei this or an earlier period. An additional fact of considerable practical importance has just come to light as the result of certain recently and confiden tially reported observations on the vaporization of gasoline. Gasoline vaporizes into an air-stream conducted over it vith re markable speed. As a consequence of this fact the rate at vhich the air moves has relatively little effect upon the concentration of gasoline arrived at in the air stream. Therefore, the frequency of air-chanr.es in ja ventilated space In vhich gasoline is handled open containers or spilled f Is not the important factor in the KB 0005240 control of the concentration of gasoline vapor, rather the impor tant factor is the extent of the euri'ace of gasoline that is In contact vlth the air stream. It follows, therefore, that (1) openings by which air may come In contact with gasoline in a ventilated space must be reduced to the minimum; (2) spillage of gasoline must be controlled with extreme care; and (p; the spraying of droplets into the air from any source must be prevented. I or the control of such exposure as may otherwise occur through the operation of any of these factors, vapors should be removed ix-om the space by being picked up at their point of origin end conducted to the outside. By these combined methods of control the concen tration of gasoline vapors in air must be kept below 5jj p.p.m. at the least. It is believed that few persons unaccustomed to exposure to 1 jj octane gasoline vill fail to develop variable degrees or discomfort if exposed for hours per day to air containing 5jj p-p.m. of such vapor. For this reason it Is advisable to achieve the maximum freedom of the air of workrooms from such vapor. The equipment to be usee should be so designee as to diminish to the minimum the need for contact of the skin of workmen with gasoline. Facilities for cleansing the skin thoroughly at. mealtime and other suitable Intervals should be provided and all workmen should be advised of the need for meticulous cleanliness. Where feasible, a barrier cream may well be used, aad in any case the use of a grease cream (for oiling the skin; should be available for use following thorough washing after routine contact with gaso line in the course of work. These procedures are recommended for the pur-pose of preventing dermatitis as the result of contact with V petroleum hydrocarbons, tuch denaatitis is rarely serious but. mat. cause considerable interruption, in the vork of individuals. ot~ viouslj, care against contamination of clothing vith gasoline nuoi be taken to avoid much more serious injury to the skin than that occasioned by contact of unclothed skin ai*ess. If conditions require periodic or occasional changes of clothing, suitable equipment (lockers, Iocke-2-- room, and clothing; should be made availa ble under- some veil-established regimen. 'toxic Exposure to tetraethyl heat: Under' the conditions of the normal commercial handling c: motor fuels containing tetraethyl lead, no slgnifican-: risk of lead absorption exists, but certain emergency methods of military handling have given rise to trouble,and certain technical opera.ifont, such as the procedures involved in the present Instance, have brought about potentially dangerous conditions c-f lead exposure, these conditions can readily be avoided by the application of certain general principles,and therefore it seems advisable to clarify the factors that influence the extent of the exposure. the safety factors in the normal ccanmerical handling of leaded gasoline are primarily tvo in number. (1; Whereas tetraethyl lead is absorbed through the human skin vith fair ease, the dilution of tetraethyl lead vith gasoline retards its passage through the skin and prevents it, for all practical purposes, vhen the dilution is of the order of magnitude of lOuu parts or more of gasoline to 1 of tetraethyl lead, (ihe concentra tion of tetraethyl lead in commercial gasoline may not exceed loth parts per million, vhile that in military gasoline, vhile not under control cf the Ethyl Corporation, has not exceeded this figure except in connection vlth certain experimental activities of restricted scope.} (} From the aspect of inhalation of vaporised tetraethyl lead put of gasoline, the difference in the volatility of these tvo engredients of motor fuel, together vlth the difference in their respective concentrations in the mixed fuel, is such that very little tetraethyl lead is given off in.the vapors of the fuel vhen evaporation takes place from an open container. (The first 10 pel* cent, of vaporized fuel contains only a minute fraction of the available lead compound.} Ac a consequence, if the fuel is handled sc as to avoid the undue risks from fire and explosion tiia, vould follow from spillage or leadage in enclosed spaces, and so as to prevent the occurrence of toxic concentrations of gasoline in the air breathed by handlers, no risk of toxic lead absorption occurs. By reason of the operation-of these tvo factors,, lus the care currently taken by gasoline distributors to avoid fires and explosions, the commercial handling, of leaded gasoline has been unaccompanied by any cases of measurable lead absorption or of lead intoxication over the period of approximately tventy years during Which such fuels have been distributed. (Certain conditions peculiar to the confined spaces of gasoline storage tanks, have resulted in some serious cases of lead poisoning among periods vhc have entered storage tanks to c a n y out cleaning and repair opera tions, without folloving standard precautions. Such cases,vhich have been reported in medical literature, shoiild not be permitted to confuse the clean-et issue under discussion.} However, there 0005243 can be no doubt that leaded gasoline can be dealt vith in such a manner as to give rise to dangerous lead exposure. Three principal factors re responsible for the production of such an hazard, - (a) spillage of considerable quantities of gasoline in an enclosed or partially enclosed space, (b) spillage or leakage of gasoline in a thin layer or on a surface that permits of its complete evapora tion, and (c) the creation of a spray vith resultant complete vaporization of the gasoline in the air. It is apparent that all the conditions that may result in the operation of the above factors must he controlled vith detailed precision in any technical operation that is intended to continue over any considerable period, of time. Lead absorption in relation to such operations must be kept vithin quite lov limits in order to avoid cumulative effects. It has been shovn- that, a reasonable degree of safety can be maintained by preventing the occurrence of lead conceittrations in the air in. excess of i.p mg. of lead (?LJ per cubic meters ox a n It is feasible and vise, however, in <* connection vith exposure to gasoline to tighten up .tannare b by >j per cent or more, for/so doing the concentration of gasoline available in the air vili usually be beneficially influenced. The basis fox* the use of lu cubic meters as a standard comes from the fact that this is the upper limit of the quantity of air breathed in by a veil developed adult at reasonably hard work in the course of 3 hours. If the working day is longer than 8 hours the permissi ble concentration of lead must be reduced proportionately. {Methods for the determination of lead in the air are appended hereto, as a basis for compliance vith these standards, and if is recommended that precise measurements be made under the ( various conditions that may exist in connection vith .present and future operating conditions - It may be unnecessary to make corresponding dieterminalions of the concentration of gasoline vapors. the experience cf the men may provide sufficient indication of the significance of the exposure to gasoline. The severity of the lead exposure, however, should not be left, to conjecture, unless virtually complete freedom from exposure can be achieved.) Practical Observations and recommendations Observation of the conditions under which the vork under con sideration is being carried out justifies certain criticisms. While recognising that the present facilities are temporary in character, previous experience and the present expectation as to the completion of nev facilities necessitate the conclusion that present conditions may remain in use for quite some time. Moreover it vas said that additional equipment similar to that nov in use vas to be introduced Into the same space. The criticisms, vhich are not intended to be unduly emphatic but merely straightforward, follov : (1) the- ventilation of the room in which the vork is done is general, rather than specifically fitted to the problem involved. For reasons indicated above this type of ventilation cannot but be Ineffective, and it Is. If additional equipment is added there vill be an Increase in the exposure, in direct proportion, at least, to the increase in the number of units. Each unit of equipment employed in the testing should be ventilated individually, in such manner as to remove rather than merely to dilute the vapors that arise from the entire operation. (2) The inevitable spillage of gasoline should not be permitted to influence the cleanliness of the space in general. All dripped o p spilled gasoline should be caught by ventilated drip pans that vill keep the gasoline off the floor and its vapor out of the air in the room. All fuel lines oust be kept absolutely tight. At present much too much gasoline lies on the floor. This \ should be cleaned up completely, and if any opportunity for future spillage to allowed to remain, floor drains and water lines must be available for washing it away promptly and completely. The use of composition floor dryer to remove gasoline, if that is intended, is unjustified for this purpose. No doubt it is satisfactory for taking up oil, but the presence of dye on the floor clearly indi cates the spillage and non-removal of considerable quantities of gasoline. (3`-j The apparatus in use is not sufficiently enclosed or free of leaks to provide safe conditions. Several modelr arc in use, presumably as an indication of somewhat less than n satisfactory performance of any. A model should be settled upon as sqpn a? possible, so that makeshift methods can be dispensed with and safety devides introduced to the maximum degree. (A) The fire hazard to all the men is greatly magnified by the fact that there Is no adequate isolation of individual units of equipment. Any further introduction of similar equipment will intensify this hazard,which in the opinion of this observer is already much too great. It is strongly recommended that observations be made to determine the extent of the lead absorption of certain of the indi viduals who have been engaged in this work, or whose exposure in the developmental process resembled that of the present operators. Samples of urine and blood can be obtained and analyses can be made that will result in demonstrating the degree of significance of the lead exposure that has occurred* Such observations will give a clue to the present need for precautions and may veil point the way to vh&t should be done in the new building that Is to be built. If the ground work is properly laid for the collection of these samples, so that their value and prupose is understood, it seems improbable that they will create difficulty. Our previous rather broad experience in this regard has given us little or no reason to fear the reaction of reasonable men. It is recognized that the occasional man Is not or does not wish to be reasonable. Careful selection of men for this purpose should obviate any difficult;. along, this line. If and when the number of persons to be examined in this way Is determined, vs shall send all the necessary containers and complete instructions. * With respect to the new building that is to house- this work, it is recommended that the plans for the installation of the testing and ventilating equipment be reviewed in the light of this dis cussion of hazards and the principles of their control. Indeed, It is understood that this Is being done and that tills recommendation is merely a confirmation of verbal statements. It is hoped that the visit to the dockland, Ohio, plant of Wright Aeronautical Corpora tion was productive of useful information in this direction. From the Kettering Laboratory of Applied Physiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio. December 27# 1944 Director