Document ByQnLqNzBb97MY0moE6Vxqgzm

fc .fr -i ih M , P j U r & f ^ A -' jCL' i t , S * t & k tM ( f a -fzv) o-rSD * i V J r v i* IP' 'rf M C M / *2 - / fau n ' r t z y ) , / f ' Z O r S . Problem s in H andling Ethyl Fluid and Ethyl By ROBERT A. KEHOE. M.D.* 19 Tv>. 0 CLEAR the way for a detailed consideration of potential dangers in the handling of ethyl finid, I shall deal very briefly with the hazards speculatively associated with the ^distribution of ethyl gasoline as disfrom other gasoline. Ten y ea - of experience and of critical in 1. vestisation have failed to reveal the & existence of danger to any group of pl'wtckinen or to the general public from .^ ^ tb e presence of small amounts of tetra- jpetby] lead in automobile fuel. Various l^a^ects of the question are being further investigated at present, but only two natters deserve mention in a practical ^'discussion of safety problems. 1. Exposure to Lead Compounds in Cleaning Storage Tanks. Tetraethyl lead alone or dissolved in gasoline slowly decomposes to yield crystalline triethyl lead compounds. Under normal storage conditions this decomposition is almost inappreciable, but over a period of years variable amounts can be found in the scale on the sides and at the bottom oi storage tanks. If the sides or bottom of such a tank are cleaned in a dry state, rely divided dust containing triethvl ]aA salts may be inhaled by unprotected workmen who may enter the tank. In halation of these compounds causes irri tation of the respiratory' mucous ment is braaes and the skin, accompanied by , S t .lent sneezing, weeping, and burning 1 o: the skin. Further exposure may * result in rapid lead absorption and acute *-* intoxication. It is a simple matter to prevent lead exposure of this type either by' cleaning the tanks in a wet state, or by the use c: air line masks. Actually, these two safety measures are employed in routine' cleaning at refineries in guarding against the inhalation of gasoline vapors. Nevertheless, since the lead hazard would not be considered of itself, the atp. tendon of refinery personnel has been reeled toward it through instructions which coincide with or supplement the current practices of tank cleaning. It C incinnati Ohio. (A p a p e r p re se n te d before the Petroleum Section. T w en tv - .yrS A nnual S afety C ongress.) should be pointed out further, that ma terials ot this type, removed from ethyl gasoline storage tanks should be buried or otherwise disposed of so that they may not be resuspended by air currents- 2. Lead accumulation on the surface of the earth. Through a variety of avenues lead compounds are being brought out of the earth and distributed upon its surface. The deposition of finely divided lead bromide by way of the exhaust gases of automobiles and airplanes which burn ethyl gasoline is only one aspect of this process. I mention the problem in this connection, not because the use of ethyl gasoline is the most important factor-- for it is not-- but rather because the whole question arose out of the investigation of the public health problems associated with the distribution of ethyl gasoline. There is no present reason- to believe that it involves danger to the public health. However, it must be recognized that a sufficient general increase in the gross daily human intake of lead from any and all sources could result in wide spread damage to health. It becomes a matter of some importance, therefore, to know how much lead we are taking into our bodies through our food ma terials and otherwise, and to keep a critical eye on the factors which affect such lead intake. This, my associates and I are attempting to do in the Labora tory of Applied Physiology in the Uni versity of Cincinnati. Hazards of Handling Ethyl Fluid The general character of the hazards in the handling of ethyl fluid is de termined by the properties of the lead compound which is its principal consti tuent. Tetraethyl lead is an oily liquid which shows a decided tendency to creep through the seams or joints of containers and pipe lines, thereby supplying abundant opportunities for leakage. Moreover, it is a heavy material, of almost twice the weight of water, so that packages of suitable size for mixing with gasoline are handled with some diffi culty, 3nd with the ever present danger of physical injury to the worker, as well as the likelihood of bursting if dropped or subjected to violence. Tetraethyl lead has an appreciable vapor pressure at ordinary temperatures, and if exposed to heat, the vaporization of the fluid develops a pressure within containers, which under extreme con ditions (conflagration) may result in the bursting of the container with igni tion of its contents, and which in the hot sun's rays causes a sudden escape of vapor when the container is opened. The oily (fat soluble) and somewhat vola tile character of the material gives it a peculiarly hazardous quality among lead compounds in that absorption takes place into the human body by way of the unbroken skin through'contact, and by way of the lungs through inhalation. The saturated vapor of tetraethyl lead in air at Ordinary temperatures contains approximately 5 mgs, of lead per liter of air, a concentration which is lethal for experimental animals after a few hours of exposure. With these characteristics in mind, it is possible to visualize the chief diffi culties which attend the manufacture, transportation, storage, and handling of ethyl fluid. The necessity for the avoid ance of leakage and spillage of fluid, and for prevention of skin contact or in halation, is apparent. And not only must safety precautions be designed for the prevention of rapid absorption and acute illness, but also for the avoidance of repeated slight exposure which may result in chronic plumbism. 1. Hazards in Manufacture The preparation of ethyl fluid con sists essentially of the blending of tetra ethyl lead with a sufficient amount of an organic halogen carrier to convert the lead to the corresponding halide when combustion occurs, and with an oilsoluble dye to give the fluid a deep color. The materials must be thoroughly mixed, and checked by chemical analysis for correctness of the quality and propor tions of the ingredients. The finished fluid is stored in tanks, or introduced into JANUARY. 1934 20 drums or into tank cars tor shipment. The control of the dangers of manu facture is relatively simple, since all the operations are carried out by a single isolated group of men who are under constant supervision. The solution of the problem of safety is found in the use of carefully constructed closed systems of pipes, pumps and tanks, with the necessary vents carried well outside working areas. General and local venti lation is employed as a supplementary precaution. The filling of barrels for shipment necessitates a break in the closed system. This operation is carried out, therefore, in a specially constructed, highly ventilated hood, equipped with safety devices which care for any acci dental spill. The difficulty is increased by the necessity for accurate measure ment of the fluid. Skin contact w'ith the materials, and inhalation of vapor is obviated through detailed regimentation of the technique of all plant operations, including the carrying out of repairs, and the main tenance of meticulous housekeeping. The adequacy of precautionary measures is checked by regular medical super vision. An integral part of the manufacturing and shipping procedures is the cleaning, testing and repainting of metal drums before refilling, and the testing of re filled drums for leaks before shipment. The hasards oi the cleaning operation are essentially negligible, since it is done by equipment enclosed in highly venti lated hoods and operated from the putside. Cleaned drums are given an air pressure test, and filled drums are tested in a specially ventilated room, by setting them with the bung down for a period of 12 to 48 hours. The slightest leak becomes readily apparent because of the spread of the deeply colored fluid into the bright new aluminum finish on the surface of the drum. Suitable warn ings are pasted on each drum, with in structions for caring for accidents, or leaks. The recognition of such dangers was responsible for the use of a specially designed metal drum, and later a special type of tank car for shipping ethyl fluid. 2. Hazards in tiie Transportation Difficulties in transportation arise largely from the fact that the fluid may pass into the custody of persons who have not been instructed adequately as to the nature of the dangers and the means to employ in avoidance of such dangers. There is the greatest necessity, therefore, for anticipating the type of handling which is given to ordinary com- modicies in transit. In fact, every effort must be made to see that no opportunity occurs for contact or exposure from the time of shipment until the material arrives at its destination, where it can be taken in charge by properly trained persons. For this reason shipping of drums, with rare exceptions, is carried out in full car load lots, or at full car load rates, so that the drums may be safely fastened in place in the car at the manufacturing plant and removed by the trained personnel of the purchaser. Where shipment occurs by boat, the drum cargo is under the supervision of a representative of the shipping plant, until it is fastened in place on an open deck of the vessel, from which it is re moved at destination under the super vision of the shipper's or purchaser's trained agent. From time to time drum shipments of fluid have been made by truck. This has been done usually to avoid a tran shipment of less than carload lots by rail. Thus a car load of fluid, shipped to some central point has been split among neighboring purchasers, each of whom has `transported a number of drums by truck. This again, merely represents the attempt to maintain the responsibility for the handling of drums in the hands of persons who are fully informed as to the proper method of handling. 3. Handling of Fluid at Refineries and Bulk Mixing Points The above paragraphs have dealt with the precautions which must be taken by the distributor of ethyl fluid, in order to see that the product reaches the purchaser without the likelihood of any injury to anyone in transit. From this point on it is necessary for the pur chaser to see that the fluid is handled only by the proper persons, that it is mixed with gasoline in proper amounts and by acceptable procedures, and that the emptied containers are returned to the distributor with the same care that was observed by the distributor. Storage. Hazards in the case of drum storage include the mechanical difficulty of handling heavy packages, the possi bility of leaks and spillage, the develop ment of pressure in the drum with high temperature, the partial solidification of the fluid at low winter temperature, and the occurrence of fire. Theft of the fluid, and tampering must also be pre vented. Obviously the fluid should lx stored where the containers can be handled with ease, where vapors will not be confined, where spilled fluid can be readily washed away, where there is pro tection from direct sunlight (in warm or temperate clim ates), and from the spread of fire, and where there is security from handling by unauthorized persons. When fluid is shipped in tank cars the chief storage problems have to do with Die transfer of the large amount of heavy fluid from the tank cars to a fluid storage tank without allowing exposure, the pre vention of leakage of either liquid or vapor from the storage tank, and pro vision against excessive cooling or heat ing. Mixing. The hazards of mixing with drums of fluid arise in moving heavy drums to the mixing site, in removing the bungs, in emptying out accurately measured amounts of fluid, in mixing the fluid with gasoline, in rinsing out the drums when emptied of fluid, and in re placing the bungs. All this should be done without leaks or spills, and it must be done without exposure, on the part of the handler, to the liquid or vaporized fluid. Moreover, any implements or equipment used in the process must be cleaned up so as to remove any oppor tunity for subsequent contact with liquid or vapor at the mixing site. The most serious aspects of the prob lem of handling fluid out of a storage tank are concerned with accuracy of measurement, the prevention of leaks in the pipe lines, and the carrying out of repairs if and when leaks develop. It is inevitable that there should be differences of opinion among the large number of persons who have purchased and used ethyl fluid in the preparation of ethyl gasoline, as to the requirements for safety. It is equally certain that if the manner of mixing were left to the discretion of gasoline distributors, there would be a wide variety of methods, equipment 3nd precautionary' measures. Especially at the beginning of this new industry, it was necessary to make a careful appraisal of the hazards. To do this some type of centralized responsi bility for the manner of mixing had to , be established. This was achieved through regulations and instructions to the purchasers Gf ethyl fluid, together with specifications for mixing equip ment. Compliance with these regula tions was made an obligation to which purchasers were bound by contract. Under this regime a high degree of uni formity has been maintained. Mixing plants are built to satisfy not less than minimal specifications supplied by the distributor of ethyl fluid. These specifications cover the storage facilities for ethyl fluid, the mixing equipment, ( Please turn to page j o ) NATIONAL SAFETY NEWS iS kT i Ethyl Gasoline ( Continued jrom page 20) Tank- suspended on a scales, and (2) a mixing weighed amounts of fluid into gasoline. Both steps are carried out locker rooms, bathing facilities, ordinary 1 through the use of an eductor on the and special protective clothing and gasoline line. Since all movements of equipment, and gas masks. m the fluid are accomplished by suction, Regulations cover all the procedures, E - and since sufficient vacuum for the including the requirements in the matter * purpose can not be obtained in the of cleanliness, clothing changes and 1 c presence of leaks in the system, it fol- similar details. Workmen are selected ^ - lows that if the apparatus moves the by a medical representative of the dis-i0 j fluid at all, there is no opportunity for tributor on the basis of physical fitness, a *kin contact with leaking fluid or in- and each man is instructed as to the TM regulations, and the dangers associated with improper handling of ethyl fluid. Storage space for drums of fluid con sists of a concrete platform at box car or truck height, with at least, three sides open to the air and a roof overhead con-'S nected with drains so that it can be _ thoroughly hosed. This platform is continuous with the mixing area, the entire & structure being enclosed with h eavy wire, locked against entrance, and being 4 of fire proof construction. The storage ,tank. f,or fluid delivered by tank car ibs i J located adjjacent to the mixinog eqhuiprmen t. halation of escaping vapor. The various factors which influence ' the magnitude of occupational hazards . of the workmen may be listed in the order of their importance as follows; . (1) The extent of the cooperation of ' refinery management in the avoidance "of irregular practices, such as unnecesT-sary sampling of fluid, the removal of ** small amounts of fluid into intermediate containers for experimental mixes, and f for the correction of errors io mixing; r. (2) the quality of the mixing cquip' ment; (3) the frequency of mixing; and " ^d(,4ie) nmue.ixi.ndgegpreeersoonf nceal,utinionfoellxoewMricnisgedprbey y , scribed instructions. Mixing of fluid supplied in drums isjjj . The importance of the last item is carried out by means of two types of /' . 'stressed at all times, but much greater equipment, one for less than full drums 0* dependence is put in the automatic of fluid, the other in which not less than/ safety afforded .by the installation of a full drum is used. In the former case ^ proper mixing equipment and adequate a special apparatus is fastened in the storage facilities, It is manifestly im bung opening, and the desired amount of -d possible to prevent departures from ac fluid as indicated by gross weight loss, 1 cepted procedures excepting as the re is drawn off by means of an eductor, J finery management and personnel give attached to the gasoline line. their willing and intelligent cooperation, In the other case, the full drum of J and unless they accept the point of view fluid is used as the unit of measure, and i that no commercial consideration can one or more drums as required are , justify the violation of a reasonable emptied by means of an eductor at- ' regulation. tached to the gasoline line, and mixed a The chief functions of the medical with the proper amount of gasoline in a tank. The operation is completed m representatives are to promote such a point of view, to maintain and improve when the eductor line has been well washed out, when all the fluid has been 4? f introduced into the gasoline, and when J : mixing plants, and to prevent any relaxa tion of caution. The periodic medical . examination of eve|-y person engaged in the fluid and gasoline have been recircu- . this work, together with occasional lated so as to obtain complete admixture, 3 study of the lead excretion of a repre The latter is an important item, for ^ Jwhen the heavy fluid is merely poured sentative group of workers, serves large ly to determine the effectiveness of the into gasoline it drops to the bottom and 'J precautions. remains as a separate layer for a long m Perhaps this is a somewhat uncommon time. N ot only would this introduce | concept of the significance of medical serious error into the composition of the a examination. Such a concept, however, gasoline, but it may also result in the does not arise from any lack of appred- accumulation of concentrated fluid at 4 . ation of medical service. Rather, it the bottom of the tank which might be / springs from the certainty that no encountered when the tank is cleaned. amount or excellence of medical care is The entire procedure of storing the 1 suffident in itself to prevent the occur fluid and mixing it with gasoline in mix rence of lead poisoning. In our opinion, ing plants which handle tank cars 0: , the only way to prevent occupational fluid is carried out in two steps, (1) T'kad poisoning is to so limit exposure , xmqr.'y'nii, 'hit *aak. van :nfm -a -s*.wagt: Ljfcat poisoning cannot occur. NATIONAL SAFETY NEWS JANUARY, 193-1