Document k3GyBoVKRemLj71eY3vqZYYD

T 3 T H A E THYL L E A D _________ A new industrial poison . TM G I U A L J I Q I L S O H ..... II.P. Professor of Medicine, Emeritus, Cornell University Medical College ' Tetraethyl lead is an industrial poison of extrordinary in te re st in medicine on account of i t s treacherous nature, varied modes of entrance into the "body and the unusual grouping of symptoms which i t may produce. These symptoms in great part are so unlike those of ordinary chronic lead poisoning as not to suggest the la tte r to anyone unfamiliar with the effects of th is soluble and even v o la tile form of metal. Thesubstance was produced f i r s t by chemists in and has long been recognized by them to be extremely toxic when carelessly handled in concentrated form. Two chemists in the !.!assachusetts In stitu te of Technology were poisoned by i t some years ago. Only recently, however, has i t s commercial use as an adjuvant to motor fuel brought i t before public attention. Chemically, tetraethyl lead is simple, being produced from three raw mater- 'f ' i " ' ' ' ia ls , lead, m etallic sodium and ethyl chloride. In manufacture a sodium lead alloy, T&ich is quite fria b le , is automatically groupd UP ia large closed re to rts called 'autoclaves" so that the added ethyl chloride may the more readily combine with i t . The comoound is further treated with steam, d is tille d and filte re d . This comparative ly simple chemical reaction requires much apparatus, however, and as in sim ilar chemical plants, despite the greatest care, valves sometimes may-leak, gaskets may become in secure and "sp ills" and "blowouts" may occur. Even under moderate pressure, ethyl chloride is several times more d iffic u lt to confine than steam. Hence, workmen may be exposed to the potential hazards of fcl) inhalation of dust of lead or i t s soditan alloy (2) the inhalation of fumes of ethyl chloride ^ .M '. . . . '' - ' either with or without admixture with lead, or (3) skin contact with the finished fluid product, tetraethyl lead. This substance is a slig h tly o ily , somewhat yellowish mobile flu id which, in undiluted strength may be absorbed through the skin as quick ly almost as nitroglycerine and fa r more readily than mercurial inunctions. The duration of exposure necessary to produce toxic symptoms varies from a few hours to several weeks, naturally depending somewhat upon the form and Quantity of the substance, whether i t be inhaled as a vapor or apolied as a flu id over a large surface of the skin, a fte r contact with an extensive "sp ill". Slight variations in the poisoning have been noted occasionally depending apparently upon personal idiosyncrasy, as observed with many other active chemical poisons. The symptoms in an average case are as follows: The patient complains of persistent and intractable insomnia, or, i f he sleep at a ll, he has unwonted and dis agreeable dreams, as of catastrophies, pursuit, etc. He notices nausea, anorexia and sometines morning vomiting. He becomes, re stle ss, nervous and weak and loses weight up to a dozen pounds in a fortnight perhaps. Subjectively the most striking phenomenon in many cases is a marked drop in both systolic and d iasto lic blood pressures. "?ith th is, there often but not invariably, is a lowering of two or three degrees in body temperature, a f a ll of several points in pulse rate , tremor of the hands, a rather characteristic fain tly ieteroid complexion and a slig h t degree of secordary anemia. If nromutly taken off work and made to stay in the open a ir and to exercise in moder ation, the patient often may soon return to work, at le a st upon some other job. In the more severe or fulminating cases, the insomnia becomes completely intractable, yielding to noha of the ordinary hypnotics. The most violent maniacal delirium ensues, as serious as the worst type of delirium tremens, with shouting, raving, visual hallucinations, and a tendency to spring from bed and run amuck. Two such patients, although carefully watched, dashed through closed windows. The systolic pressure may fa ll below 90;-even to 80 in several cases observed. The p atien t will take neither food nor drink and in consequence the tongue and mouth are parched and the urine secretion is diminished. Lead is obtained in large quantity from the stools, hut the urine in most cases remains p racticelly normal and lead has not been found in i t in all caaes. Tith only two or three exceptions, patients with violent delirium have died from exhaustion in from 2h to 72 hours. Of the 12 deaths recorded, a ll took place in delirium. The w riter has had the opportunity of observing 93 cases of a ll grades and not one of them remotely suggested the ordinary clin ical picture of chronic lead poisoning. There were no paralyses, there was no d istin c t "lead lin e" upon the giras, obstinate constipation was not present and although vague abdominal te stic u la r and thoracic pains were complained of occasionally, the intense and typical "lead colic" centering about the umbilicus was not once complained of. "Stippling" of the red corpuscles was pnesent in only about one-half of the cases. *n some instances carious anomalies presented. For example, one patient, a chemist, who had been testing the manufacturing processes in the work-room where most of the poisoning occurred, f e lt weak and slep t poorly, but although h is systolic pres sure f e ll to 30 and an exceptionally heavy p recipitate of lead was obtained from the stools, there was no delirium, nor was the p atien t a t any time bed-ridden. There was no "stippling" of the red blood ce lls and traces only of lead were found in the urine. Convalescence, as might be expected, is usually much protracted. The lowered blood pressure, general muscular weakness, loss of weight and insomnia are slow in being overcome and although many pationts have returned to lig h t work in other occu pations at the plant, many have occupied two or three months in complete recovery. In no case thus f a r observed, however, have any of the typical symptoms of chronic piunbism been found, o r have there been any mental secuela a t a ll. The following account leaves no doubt that the manufacturing process of tetraethyl lead i s an Tira-hasardous industry comparable in danger with those of making high explosives and many chemicals such as the an ilin es, strong acids and alkalies,war gases etc. But lik e those industries, i t is quite capable of future control and regu latio n . The en tire hazard of manufacture has been confined to two Coooanies with a third which is concerned in adding to the original tetraethyl lead, bromine to make i t more effective fo r use as an adjuvant to gasoline when diluted one thousand times for t motor fuel, plus the addition of an in e rt coloring matter to render th is diluted product called "ethyl gasoline", distinguishable from ordinary gasoline. These three Companies were well aware of the poisonous nature of undiluted tetraethyl lead and th eir medical staffs a t the very beginning, formulated standards for protective equipment for the workmen employed, such as rubber su its and gloves, masks, e tc ., besides elab orate general hygienic regulations. They also in stitu ted extensive experiments upon animal8 to determine a ll the effects of the poison in a ll i t s forms and dilutions. These experiments were not alone conducted in th eir own laboratories, hut in the United States Government Bureau of Mines laboratories and the Industrial "Hygiene laboratories of Columbia University. One of the two manufacturing Comoanies which was conducting only a small experimental manufacturing process, has given th is up for various reasons, so that at present only one Comoany is conducting th is patented process. '.feanwhile, the manufacturing processes have constantly been improved by being made more and more automatic. But in the e a rlie r phase of the manufacture while new construction was going on parallel with production, accidents with machinery occurred and the deniorable incidents shove described followed. Some fifty -fiv e patients were sent to the Heconstruction Hospital in Kew York City because i t maintains there a special clin ic for the treatment of and research in industrial diseases and accidents. Many of these patients were not bed-ridden and showed very few symptoms but were sent in merely for observation and research. They long ago returned to othsr work. Nevertheless, the sensational public press, not distinguishing that tetraethyl lead can only he used as an adjuvant to motor fuel in a one to one-thousand dilution with gasoline and mistaking the fluid for a "gas", broadcast the most sensational reports implying that the manufacturing Companies were deliberately poisoning the public with lead in the form of what they variously de scribed as "Loony Gas", "tystery Gas", etc. As a resu lt, various local and state Health Boards began to forbid i t s us8 within th e ir ju risd ictio n . These restrictio n s (in every instance but one) in the lig h t of proper information, have been withdrawn. - u- A one-to-one-thousand dilution of any poison is a very different thing from i t s fu ll strength. Carbolie acid, for instance, is hazardous to make or handle in fu ll strength, "but in a one-to-one-thousand d ilu tio n i s a valued antiseptic. I t never was intended that the general public should have any opportunity to handle the concentrated tetraethyl lead and the f illin g stations where i t is added to gasoline fo r public use as the one-to-one-thousand dilution are now operated under as careful protective regulations as are the manufacturing processes themselves. As a matter of fact, in a number of States in the mid-west and south, the dilute "Ethyl Gasoline8 has now been in general public use in over 20,000 service stations for over two years, 300.000.000 gallons have been used, and no cases of lead poisoning, either acute or chronic have been discovered. In an experimental garage maintained by a large motor company a number of workmen constantly exposed where "Ethyl Gasoline" had "been in use fo r over two years, were subjected to thorough physical examination to determine the presence of lead or any of i t s toxic symptoms in their bodies, with entirely negative resu lts. Meanwhile, the United States Bureau of Mines Laboratories, a fte r a year's experimentation with a large number and variety of animals exposed daily to the exhaust fume8 of a motor using "Ethyl Gasoline" in five times the strength employed by the public, has reported o ffic ia lly that such exhaust fumes are non-toxic. Moreover, the te tra ethyl lead i s decomposed by combustion. Of course, the public must learn not to use "Ethyl Gasoline" fo r cleaning or washing purposes or any other purpose than that fo r which i t legitim ately is intended, i . e . , as a motor fu el. "Ethyl Gasoline" is colored red as a warning against i t s ill e g it imate use. The reasons why "Ethyl Gasoline" is so important a fuel for use wherever' gaso line engines are employed whether in the Army, ITavy or Aeroplane services, or by the general public may thus be summarized. 001768-8 - 5- 1. I t will enable the employment of a new high compression engine which cannot he operated successfully with ordinary gasoline. 2. I t will thereby increase motor power and, i f in universal use, would conserve, as estimated, one-fourth of the world's motor fuel sttpnly. 3. I t will enable a reduction in size and weight of motor engines. U. f t removes the "knock* from present motor engines and makes them ran more smoothly with increased power. 5. The carbon monoxide concentration of exhaust fumes would be reduced in the same degree that gasoline combustion would be conserved in the motor engine. 00176S-9 - 6-