Document mqZYk8LNKzer0wYkV7bq6Ew5J

TETRAETIIYL LEAD - THE DISPOSITION OF AN INTERNATIONAL CHEMICAL HAZARD. by Robert A. ilehoe, a.D. From `Hie Kettering laboratory in The Department of Preventive Medicine and Industrial Health, College of Medicine, University of Cincinnati. 1. introduction. This discussion of an international problem of occupational and public health, more than thirty years after its emergence, and at a time when but a few persons appear to be concerned about it, may seem to have little justification. Tetraethyl lead has long been accepted generally as a valuable ackiitiife to gasoline for use in automotive and aeronautical gasoline, and satisfactory means have been found for tho control of all of the occupational hazards that have been associated with its production, its transportation, and. its addititfYl to gasoline. Inasmuch as gasoline containing tetraethyl lead in commercial concentrations, when distributed through normal commercial channels and when used for its intended purpose, is not appreciably store dangerous for its handlers and users than are the petroleum hydrocarbons of which it i3 mainly composed, no further reference to this aspect of the matter need be made here{l). The question of the extent and significance of the contamination of urban atmosphere with lead from the exhausts of automobiles was raised long ago for investigation, and has been under examination in one way or another and from time to time, over since. A degree of concern on this score has reappeared recently in at least one section of tho United States in connection with the general problem of the pollution of the air with products of the exhausts of F F 0003889 N9788 gasolines In the United States and Canada, by a assail increment, and by the consideration of the matter on the pare f the United f.tatcs Public health Service, when consulted by the manufacturers and distributors of antiknock additives in this country, and by the issuance of a formal report thereon, by the Public .health Service<2^\ further stimulus to some reexaiaiaation of the entire problem relative to the use of lead-containing antiknock preparations^-- has arises out of technologic considerations that have prompted said initiated the us of teirajsethyl lead as a suf&esscnt, or perhaps as a substitute in whole A' * or in part, for tetraethyl lead. It is not the purpose of this paper to discuss the hygienic issues involved in the aforementioned recent developments in the application of lead compounds to tha production and distribution of high-octane autossubile fuels. Evidence concerning the significance of those developments in relation to industrial and public health has been assembled elsewhere ami will bo obtained ami published tsar fully in due course. .Rather, it is our intention to call attention, briefly, to certain policies and procedures instituted in 1923 by tho {at that time) sol edistributor of lead-containing antiknock compounds, with the full co-opcration of the fat that time) solo saunuiocturor of tetraethyl iwod, acting with, the full knowledge and the informal advice, frens tixao to tlrae, of tho United States mobile Health Service. These policies and procedures,maintained ana extended here and abroad since 1928, with modifications and improvements indicated by extensive research and applied and tested by practical experience ia several industrial organisations now involved, have surrounded a hazardous chemical industry of international proportions with hygienic safeguards which have proved to be highly effective. This is not the time or place to talk of details, nor would any useful purpose be served by an attempt to .give credit where credit is * 0008890 3 duo to the may individuals and groups that have contributed importantly to the success of a joint effort. Certain principles hove evolved out of the experience of the years, however, and any now be visualised. That those principles are said to have evolved "'out oi experience'' is a plain statement of fact, and in the fora presented here they are the product of retrospective synthesis. They my Si the core useful for their simplicity and for their applicability to other hygienic problems in the complex fabric of tandem industry and technologic life. 2. Certain Principles of Industrial l&xiiclne and Hygiene as Applied in The gaaulacture ana Traasportat ion of I&.-ad*ontalalag Hntixaaek Compounds and in Their Introduction into gasoline. ii) Physiologic ana ^xicologiCyfnvestig'Stioa The first provision for the introduction and couusercial exploitation of tetraethyl lead on a broad base lay in a program o.i investigation which would reveal its overt potentialities for injuring persons who aight be f-A-s / subjected to exposure thereto at any point in the operations. That *** principle r' was not recognized and acted upon early enough to ward off all ;rious trouble, is a .fact of history which has served to dramatise the validity of the principle rather than to vitiate it. Cufflee it to say, here, that after a tragic start which halted further commercial activities for a tira, and brought forth an extensive interim investigation by the United States Public Health service, the industry reauned its course in 1323, and this time developed the various parts of its hygienic regimen in proper sequence. Every anticipated procedure was planned with un eye to the careful interpretation of the results of preliminary toxicologic investigations, and was carried out under a technologic scrutiny of the resultant environmental conditions said under u clinical surveillance of the personnel involved therein. 3 point which should be emphasised in this relationship ia that the #* 0008891 4 toxicologic information obtained by more or less conventional procedures of the laboratory were not sufficient for the purposes of industrial hygiene. Such information had to be translated into technologic methods for the quantitative measurement of the relevent features of the environmental hazard, and, more importantly, into meaningful techniques for discovering the physiological and clinical responses of exposed personnel and determining their significance. VK impulse to inject some collateral comments into this discussion at this point is almost irresistible, for indeed a volume could be written on the irrelevance and the futility of much of the conventionalized toxicologic rigsmarole that has developed during the past two decades, in so far as effective measures of industrial and public health are concerned. Multiplicity and complexity of procedure have been substituted for clarity of thought and singleness of purpose in ascertaining the facts concerning human behavior in a potentially harmful environment. Let the physician, especially, consider the facts of biological life and remember always the classic axiom that "the proper study of mankind is man". This is not to say that there is not virtue and necessity in purposeful and well designed animal experimentation in advance of human experience. Many of the alleged refinements of such experimentation, however, and a large proportion of those not concerned with physiologic mechanisms, are comparatively sterile and wasteful of time and money, in the sense that the time and money could better be spent in the development and application of methods for the investigation of the reversible responses of the human organism to noxious or potentially noxious environmental conditions. Be these controversial matters resolved as they may, the fact remains that it is necessary, in confronting the prospect of human exposure to unexplored chemicals and physical agents, to investigate,in experiments with animals /the means of aceess of such substances or forms of energy into the complex organism, to establish, at Kf 0008892 -5 least in a descriptive manner, the effects of such an invasion in terms of dosage and duration of exposure, and to discover, if possible, means by which the threat or the actuality of the attach on the organism can be ascertained before it shall have caused serious or irreversible damage. With these facts available to the extent that is mandatory under the circumstances, the essential features of environmental control and of medical supervision come to light, at least in preliminary form. (3) The Assign of Commercial Operations The primary features of the production and distribution of tetraethyl lead, from the hygienic viewpoint, were predetermined by Its intended use as an antiknock agent in a low concentration in gasoline. IS it was to achieve the wide use which alone would Justify its continued existence, a large quantity had to be manufactured, transported to appropriate sites in appropriate containers, and introduced in exact quantities into gasoline. All of tha operations that involved opportunities for human contact with, or.hasardous exposure to, tills toxic material had to be subjected to direct and thorough hygienic control. The feasibility of .such control in the nation-wide and ultimately world-wide automotive transport industry depended obviously upon the limitation of such exposure to as few sites as possible and to comparatively small numbers of exposed personnel who could be instructed and supervised both technically and medically. There was no hope that tragic results could be avoided through the more issuance of instructions to the persons responsible for the various operations. Such a pious gesture would only have been a disclaimer of responsibility. Consequently careful consideration had to be given to the development of a pattern of conacrciul operations to which the essential hygienic regimen could be applied. This resulted in the concentration of manufacturing activities at sites where expert technical and hygienic and kr 0008893 6 medical facilities and personnel could be assembled and joined in a co-ordinated effort to examine and improve manufacturing processes and equipment^ aKtJMaWKB*3BSaBEi^ and also supplementary measures of environmental control, as well as satisfactory medical procedures, all in the interest of reducing the occupational hazards and eventually bringing them under complete control. It is important to recognize that this can almost never be done completely in a new industry in advance of the work of industrial production. The best of planning in advance is certain to be ladling at certain points and to require modification in practice. Careful consideration had to be given to the problems of transportation, to the end that accidents in transit would be reduced to the minimum, and that no person should incur exposure inadvertently or without knowledge of the risk incurred and of the means of avoiding such risk. This required the use of special containers, distinctive labeling, special handling adapted to the required methods of transport by rail, ship and truck, with particular reference to transportation from consigner to consignee without intermediate handling by untrained personnel. Fully informed employees of the con signor were always available at sites indicated on the labels as being subject to the call of transport personnel for advice and direct assistance according to need. The acceptance and the handling of shipments at destinations were dealt with by instructed personnel, so as, under normal circumstances, to leave no opportunity for mistakes of judgment or performance by uninformed persons. The decision was arrived at early to limit the sale and distribution of antiknock compounds to gasoline refiners, and to make every reasonable attempt ^ J maintain at a minimum the number of sites at which the antiknock preparation ^ was to be mixed with gasoline. (The importance of this strategic move, in relation to the numbers of persons who were to handle the concentrated material, may be 000S8 4 7 appreciated by noting that the initial plan, prior to 13S3S .and based on convenience of distribution, rather than on safety, was that of dispensing the antiknock compound iron osall cans supplied to the operators of gasoline service stations. The continuation of this procedure would have subjected hundreds of thousands of service station attendants to a potentially severe and uncontrollable hazard.) &xtel equipoent for mixing was designed Caacl further developed subsequently to Unit the exposure of nixing personnel to aliaost negligible proportions} by the distributor of the antifenach compound, and the purchaser was required (by contract) to build and ploy equipment based on a blue print of tiisraodel. Detailed instructions were issued for the mixing procedures asud for the application of hygienic measures therein, and a regimen of technical supervision of the mixing plants and of medical selection mid supervision of the nixing personnel iersployecs of the oil coapanies) was devised and carried out by the distributor of the product. The authority of the technical and nodical staff of the distributor to supervise and regulate those operations was provided by contract. The nature of this rogintca aceo to achieve complete control of the occupational hazard. Ho case of tetraethyl lead poisoning has ever occurred in connection with these rJUdUig operations in the United states ami Canada, and it is believed that h o c have occurred in other 'V countries in vfoich this regimen has been followed consistently. CCocumcattary evidence is not sufficient to substantiate fully the latter part of this statement, but its essential accuracy is not in doubt.) 3. Special Situations and Supplementary Procedures . j_ >* {1} Gasoline*^/torage yLftim ja unanticipated hazard of serious proportions appeared within the refineries anti storage plants of thc-cg oil companies after a few years of operation. HE 0008695 in that men engaged in cleaning and repairing large tanks (more than 1GQO barrels in capacity) used for the storage of leaded gasoline were found to be subjected to hazardous exposure to tetraethyl lead and its decomposition products. The problem was investigated and adequate precautionary measures for the control of this hazard were developed and issued to all of the distributors of gasoline soon after the first difficulties occured. Afterwards, to the extent that these precautions were applied faithfully, no further cases of poisoning developed. It has been difficult, however, to achieve and maintain a general awareness of this hazard, and to ensure the application of the precautions at all outlying points of storage throughout the world, and especially in those tinder the control of military organizations. Frequent changes in military personnel, and the practice of farming out the maintenance jobs to contractors who may not understand the problem, plus the difficulties of access to some of these tanks, have been responsible for a number of serious casualties. Never the less, the distributors of lead-containing antiknock compounds have persevered in their efforts to inform and remind the appropriate persons in military circles concerning this matter. Such difficulties have not been limited strictly to military storage tanks. Because of the geographic scope and complexity of the distribution of leaded gasoline in the United States and Canada, the distributors of antiknock compounds have found it necessary to set up elaborate systems for exchanges of information and for on-thespot consultation between their organizations and those of the oil companies, whereby the cleaning of gasoline storage tanks is supervised by trained personnel throughout the country. (2) Operating manuals. Another feature of the hygienic regimen in the varied operations of the tetraethyl lead industry, to which reference must be made for the sake of tfjr 0008896 -3 - coiawletness, is the use of detailed operating manuals ia which, generally, but act without exception, instructions for all operations are accompanied by instructions with respect to safety end health. These are put into the hands o the appropriate people and are used regularly both la instructing the new personnel and reminding aor experienced persons. These manuals are reviewed iron tisjo to time and bxought up-to-date. In this aaaaor, a high degree of uniformity at instruction and performance is maintained. It is also the practice to reproduce certain essential operating procedures {such as those concerned with aliasing operations, the cleaning of gasoline storage tanho, and the handling of concentrated antiknock compounds in research and testing laboratories) on placards, wad to peat the latter ia convenient places for reference by the operators. Familiarity end compliance with the instructions in manuals and placards is reiafonacod by close supervision and periodic reindoctrination of all operating personnel. (3| Consultation with occupational health authorities ia areas of operation. it still further procedure, which grow out of the considered policy of the .^soriCtm tetraethyl lead Industry to conduct itself responsibly ia its operations and in its informal relations with the United States Public Ilealth Service in the absence of any specific legal regulations or legislative enactments ia iho United States, ms that of lafcwsing the responsible authorities, in various other countries into which its product was to bo introduced, of all of the hygienic facts and considerations that had cos to light out of research and experience. On reason for this policy, no doubt, was the hop of avoiding legislative and regulatory provisions which might complicate international operations sad provide serious obstacles to the establishment and maintenance of an essentially uniform program ox K ^ 0 0 0 8 8.9 7 10 Industrial hygiene. Probably, however, the principal virtue of such a policy in international commercial operations of an hazardous type, is that of offering full information and co-operation to responsible health authorities and seeking in return their advice and assistance la achieving the best results within their area of responsibility. Almost without exception this has been the outcome of interviews and exchanges of information with governmental authorities in countries outsidd the united States, and the results, in terms of a reasonably uniform international program of industrial medicine and hygiene, have been generally satisfactory. In a world of nations which have failed so signally to find common ground for applying their resources and skills to the basic needs of their peoples, it has been a refreshing experience to encounter reasonableness and willingness to help, singleness of purpose, and general freedom from personal and national prejudices among our own professional colleagues in relation to this international problem of occupational health. I would be negligent and ungracious were I to fail this here to give testimony tc/nucleus of international understanding and good will. (4) Medical consultants in operating areas. One other point may be worthy of brief mention in passing, because of its relevance to the policy and procedure referred to in the previous paragraph. It has been the practice of the American and British companies in this industry to seek out and engage the services of competent and reliable medical consultants in each of the countries in which their product is used. The duties of these consultants vary with their location and the extent of the operations within their area of responsi bility. In general, however, these consultants have recognized competence in the field of occupational medicine in their own right, and are informed concerning the medical i^roblems, policies and procedures of this industry. It is their function to act professionally for the industry in seeing that the laws and practices of their own country, as well as the requirements of the chief medical advisors of the industry, U-Z 0008638 H are complied with, and that there is an adequate exchange of pertinent information. Through such a professional arrangement every reasonable provision is made for the instruction and medical supervision of those whose exposure to tetraethyl lead my be hazardous, for the attention of all concerned to their personal and occupational responsibilities^and for the maintenance of an hygienic regimen which for more than thirty years has demonstrated its adequacy when it is adhered to with persistence and understanding. References CD iiohoe, Robert A., Thaasann, Frederick, and Cholak, Jacob; .4a appraisal of the lead hazards associated with the distribution and use of gasoline containing tetrathyl lead. Part Ij Jour, of Ind.Iiyg., 15: .100-128, 1034; Part if'. The occupational lead exposure of filling station attendants and garage mechanics. Jour. Ind.Syg. and Toxicol., 18: 42-63, 1936. 2) U.S. Sept, of Health, Education, and Welfare. Public Health Service, Public Health Aspects of Increasing Tetraethyl Lead Content in Motor Fuel. Public Health Service Publication No.712, 'Washington D.C. 1939 \( 000(3699