Document DM9y3gOy9dz5EjRbBpOLLoxnd

TETKATTiIYL LEAD THE DISPOSITION OF AN Kmm\TIQEUL CHEMICAL HAZARD. by Hebert A. Kehoe, M.S3. From Th Kettering Laboratory In The Department o Ibrovetttive fcSedicin and Industrial Health, College of Medicine, University of Cincinnati. .1. Introduction. This discussion of an international problem of occupational and public health, iooro than thirty years after its esaergenc, and at a tins when out a few persons appear to fe concerned about if, nay seen to have little ' v justification. Tetraethyl lead has long been accepted generally as a valuable additive to gasoline for use in automotive and aeronautical gasoline, and satisfactory means have been found for the control of all of the occupational aasuras that have boon associated with its production, its transportation, ana its addition. to gasoline. Inasmuch as gasoline containing tetraethyl lead in c<xacaercial concent rations, whoa distributed through normal commercial channels and when used for its intended purpose, in not appreciably wore dangerous for its handlers and users than arc the petroleum hydrocarbons of which it is i.Kiinly composed, no further reference to this aspect of the matter need be made aore^dX 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, ever since. A degree of concern on this score has reappeared recently in at least on section of the United States in connection with tho general problem of the pollution of the air with products of the exhausts of automobiles. This has been heightened to some extent by the decision of the 2 gasolines in the United States and Canada by a small increment, and by the consideration of the matter on the part of the United States 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 stimulus to some reexamination of the entire problem relative to the use of lead-containing antiknock preparations^/ has arisen out of technologic considerations that have prompted and initiated the use of tetransethyl lead as a supplement, or perhaps as a substitute in whole 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 the production and distribution of high-octane automobile fuels. Evidence concerning the significance of these developments in relation to industrial and public health has been assembled elsewhere and will bo obtained ana published more fully in due course. Farther, it is our intention to call attention, briefly, to certain policies and procedures instituted in 1926 by the (at that time) sole distributor of lead-containing antiknock compounds, with the full co-operation of the (at that time) sole manufacturer of tetraethyl lead, acting with the full knowledge and the informal advice, from time to time, of the United States Public Health Service, These policies and procedures,maintained and extended here and abroad since 1926, with modifications and improvements indicated by extensive research and applied and tested by practical experience in several industrial organisations now involved, have surrounded a h&sardous 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 /< 0008958 due to the many individuals and groups that have contributed importantly to the success of a Joint effort. Certain principles have evolved out of the experience of the years, however, and may now be visualized. That these principles are said to have evolved ''out of experience" is a plain statement of fact, and in the form presented here they are the product of retrospective synthesis. They may be the more useful for their simplicity and for their applicability to other hygienic problems in the complex fabric of modern industry and technologic life. 2. Certain Principles of Industrial Medicine and Hygiene as Applied in The Manufacture and Transportation of Lead-Containing Antiknock Compounds and in Their Introduction into Gasoline. i- Ci) Physiologic and ^oxicologic Investigation, The first provision for the introduction and commercial exploitation of tetraethyl lead on a broad base lay in a program of investigation which would reveal its overt potentialities for injuring persons who might be subjected to exposure thereto at any point in the operations. That fcfeset principle was not recognized and acted upon early enough to ward off all serious trouble, is a fact of history which has served to dramatize the validity of the principle rather than to vitiate it. Suffice it to say, here, that after a tragic start which halted further commercial activities for a time, and brought forth an extensive interim investigation by the United states Public Health Service, the industry resumed its course la 1923, and this time developed the various parts of its hygienic regimen in proper sequence. Every anticipated procedure was planned with an 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 and under a clinical surveillance of the personnel involved therein. 3 point which should be emphasized in this relationship is that the 0008959 4 toxicologic information obtained by more or less conventional procedures of the laboratory were not sufficient for the purposes of industrial hygiene. iuch information had to be translated into technologic methods for the quantitative measurement of the relevant features of the environmental iiaaard, and, i^or importantly, into meaningful techniques for discovering the physiological and clinical responses of exposed personnel and determining their significance. 3SS impulse to inject some collateral comments into this discussion at this point is ahaost irresistible, for indeed a volume could be written on the irrelevance and the futility of ouch of the conventionalised toxicologic rlgasserol 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 tho facts concerning human behavior in a potentially harmful environment. Let the physician, especially, consider tho facts of biological life and remember always the classic axiom that *'th proper study of mankind is sun". This in not to auy that there is not virtue and necessity in purposeful and well designed animal experimentation in advance of human experience. I'any of tho alleged refinements of such experimentation, however, and a large proportion of those not concerned with physiologic mechanisms, arc comparatively sterile and wasteful of time and money, in tho sense that tho tine and money could better be spent in tho 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 ^tho means of access of ouch substances or forms of energy into tho complex organism, to establish, at -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 attack 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. (2) 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. If 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. Ml of the operations that involved opportunities for human contact with, or hasardous exposure to, this 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 fox 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 commercial 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 K 0008961 medical facilities and personnel could be assembled and joined in a co-ordinated effort to examine and improve manufacturing processes and equipment^ 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. 1110 best of planning in advance is certain to be ladling at certain points and to require jaodification in practice. Careful consideration had to be given to the problems of t raasportation, 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 handlingadapted 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 0 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 to maintain at aiuinimum 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 He 0008962 -7 appreciated by noting that the initial plan, prior to 132(3 and based on convenience of distribution, rather than on safety, was that of dispensing the antiknock compound from small 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.) rSodel equipment for mixing was designed (and further developed subsequently to limit the exposure of mixing personnel to almost negligible proportions) by the distributor of the antiknock compound, and the purchaser was required (by contract) to build and employ equipment based on a blue print of tils model. Detailed instructions were issued for the mixing procedures and for the application of hygienic measures therein, and a regimen of technical supervision of the mixing plants and of medical selection and supervision of the mixing personnel (employees of the oil companies) was devised and carried out by the distributor of the product. The authority of the technical and medical staff of the distributor to supervise and regulate those operations was provided by contract. The nature of this regimen accordance^with the hygienic provisions of his medical advisors. Sts effect was to achieve complete control of the occupational hazard. No case of tetraethyl lead poisoning has ever occurred in connection with these mixing operations in the United states and Canada, and it is believed that no have occurred in other A countries in which this regimen has been followed consistently. (Documentary 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 An unanticipated hazard of serious proportions appeared within the refineries and storage plants of theft* oil companies after a few years of operation, 0008963 a la that utiri engaged in cleaning and repairing large tanks Caere than 1003 barrels in capacity) used for til storage of leaded gasoline were Sound tc 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 distributers oi gasoline soon after the first difficulties secured, Afterwords, to the extent that those precautions were applied faithfully, no further cases' of poisoning developed, It has been difficult, however, to achieve and uintala 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 under th control of military organisations. Frequent changes la military persona!, and the practice of fansing out the maintenance Jobs to contractors who may not understand th problem, plus th difficulties of access to some of these tanks, have been responsible for a swasher oi serious casualties. Sever the less, the distributors of lead-containing antiknock compounds have persevered in their efforts to inform and rasxnd the appropriate persons in Mliter? circles coaceraiBg- this cutter. Cuch difficulties have not been, Halted strictly to military storage tanks. Because of th geographic scope and complexity of the distribution of leaded gasoline in the United States and Canada, the distributors ot antiknock compounds have found it accessary to set up elaborate systems for exchanges of information ami for cn-theepot consultation between their organisations and those of th oil companies, whereby the cleaning of gasoline storage tanks is supervised by trained personnel throughout tiie country, C2) 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 KE 0008964 -9 - coapletness, is the use of detailed operating manuals la which, generally, but not without exception, instructions for all operations are accompanied by instructions with respect to safety and health. These are put into the hands of the appropriate people and are used regularly both la instructing the new personnel and reminding more experienced persons. These manuals are reviewed from time to time and brought up-to-date. In this manner, a high degape of uniformity of instruction and performance is maintained. It is also the practice to reproduce certain essential operating procedures (such as those concerned with mixing operations, the cleaning of gasoline storage tanas, and the handling of concentrated antiknoclc compounds in research and testing laboratories) on placards, and to post the latter in convenient places for reference by the operators. Familiarity and compliance with the instructions in manuals and placards is roinforraeed by close supervision and periodic reindoctriaatioa of all operating personnel. (3) Consultation with occupational health authorities in areas of operation. A still further procedure, which grew out of the considered policy of the American tetraethyl lead industry to conduct itself responsibly in its operations and in its informal relations with the United States Public Health Service in tho absence of any specific legal regulations or legislative enactments in the United States, was that of informing the responsible authorities, in various other countries into which its product was to be introduced, of all of the hygienic facts and considerations that had come to light out of research and experience. One reason for this policy, no doubt, was the hope of avoiding legislative and regulatory provisions which might complicate international operations and provide serious obstacles to the establishment and maintenance of an essentially uniform program of KE 0008965 - 10 - industrial hygiene. Probably* however, the principal virtue of such a policy in international conaereial operations of an hazardous type, is that of offering full information and co-operation to responsible health authorities ond seeking in return their advice and assistance in achieving the best results within their areas 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 prograai 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 basicneeds 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 to/nucleus of international understanding and goon will. (4) Sedical consultants in operating areas. Ono other point may be worthy of brief mention in passing, because of it3 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 ia each of the countries in which their product is used. The duties of these consultants vary with their location and the extent ox the operations within their area of responsi bility. in general, however, these consultants have recognised competence in the field of occupational medicine in thoir own right, and are informed concerning the medical problems, policies and procedures of this industry. It is their function to act professionally for the industry in seeing that tho laws and practices of their own country, as well as the requirements of the chief medical advisors of the industry. K 0008966 u are complied with, and that there is an adequate exchange of pertinent information. Through r.uch a professional arrangement every reasonable provision is made for the instruction and rsodical supervision of these whoso exposure to tetraethyl lead say be hazardous, for the attention of ail concerned ^ to their personal and occupational rosoonsibilitieaj und for th isaintenaac of an hygienic reglnen which for cor than thirty years has demonstrated its adequacy when it is adhered to with persistence and understanding:. 4. References Cl) r.:;hoe, Robert A., Thttmaa, Frederick, and Cbolak, Jacob; Aa ; appraisal of the lead haaarda associated with the distribution and us of gasoline containing tctrathyl lead, Fart X; Jour, of Xnd.Hyg., 18: 100-128, 1934; Part ll\ . The occupational loud exposure of filling station attendants and garage mechanics. Jour. Ind.Hyg. and Toxicol,, IS* 43-83, 1938. <2) U.S. Bc-pt. of Health, education, and Welfare, Public Health Hervice. Public Health Aspects of Increasing Tetraethyl Lead Content in :-iotor Fuel, i'ubiic Health service Publication &>.i2, Washington U.C. 1959 K 0008967