Document LJoZY7rbrNakk9ok61ryX6JJq

THE LESSENIKG hfENACE OF BENZOL POISONING v IN AMERICAN INDUSTRY* ALICE I h H I L T O N , M.D. IN THE issue of The Journal of the use of benzol in industry and its American Medical Association for possible harmful effects. The work of March 4,1922,there appeared an this Committee was prolonged for article over my name entitled "The three ycars and in May, 1926, a final Growing Menace of Benzcnc (Benzol) report was issued (1) (2) in which were Poisoning in American Industry." described the chief industrial uses of This embodied the results of nn inquiry bcnzol, the methods of use, and the into the industrial use of bcnzol at the incidence of benzol poisoning among time, made with the assistance of workers as determined by clinical manufacturers and insurance com- symptoms together with examination panies. Only sis years hnve elapsed of the blood. A quantitative estima- since that date, but so great have been tion of benzol in the air of factories the changes in manufacturing proc- was made, and by checking up the esses during this short period that I blood picture of those examined with , am impelled to write a brief report on the air analysis it was possible to dethe now lessening danger from benzol termine the lowest concentration of '#- in industry. Were I to wait another benzol in the air which might bring I year it is probable that the showing about a leukopenia. It was found that ` would be even more favorable. 32 per cent. of the workers examined ': The credit for this great and bene- had leukopenia, mild or pronounced, ' ficent change should be given pri- and that this occurred in workrooms `-marily to the Chemical and Rubber with good exhaust ventilation and t t Sections of the R'ational Safety Coun- 4,an association of industrialists and low atmospheric contamination, aa low as 100 parts of benzol per million companies writing industrial insur- of air. The Committee was thus ance, which at the annual meeting in "forced to conclude that the control Detroit in the fall of 1922 appointed a of the benzol hazard (except where the committeei to study and report on the substance is used in completely closed J Received for publication April 9; 1928. `The Committee was constituted .as follows: C.-E. A. Winslow, Yale, Chauman; Leonard Greenburg United States w.Public Health Service, h e Chairman; S. Paine, Aetna Life Insurance ComY, Secretary; H. Bradahaw, E. I. du nt de Nemours L Company; J. W. S. ady, M.D.,Massachusetts General Hos- systems) is exceedingly difficult; that in practice, systems of exhaust ven- pital; A . C. Fleldner, United States Bureau of Mines; C. F. Horan Hood Rubber Company: L. E. Weber, bonsu!ting Chemist. J. M. Weiss, Manufacturing Chemlsd Association. 227 ._ 228 THE JOURNAL OF INDUSTRIAL HYGIENE tilation capable of keeping the concentration of benzol in the atmosphere below 100 parts per million are extremely rare; and that, even when thisisaccomplished,there remains a decreased,but substantial, hazard of benzol poisoning." They recommended the substitution of toluol and xylol for benzol, and described experiments carried out at Yale University by J. J. Batchelor (3) which showed that these homologues of benzol are far less toxic than benzol itself, producing only a slight anemia and having no effect on the leukocytes (4). Even before the publication of the Committee's final report, the changed attitude of industry toward the use of benzol had become evident. A large shoe company which had used benzol in cement wrote me that because of its experience with one girl employee who had excessive and irregular menstruation it had abandoned the use of benzol although the new solvent involved the expenditure of $150 a day more than the old. Machine shops spraying coatings began to use lacquer made with toluol. Many rubber factories returned to the use of petroleum solvents for spread rubber goods and for most of their cements. In dry cleaning, benzol W M already disappearing, and the protests of the organized painters against the use of this thinner in quick-drying paints were beginning to have some effect. It was, however, the introduction of rubber latex (5) as a substitute for rubber dissolved in benzol that made possible the greatest changes in the benzol using industries. Latex is the milky fluid which is drawn off from the rubber tree after slitting the bark. The practice in rubber plantations has always been to coagulate it at once, make it into sheets, a6d ship it in this form, but by this new method coagulation is prevented by the addition of ammonia, which inhibits the growth of coagulating bacteria, and the latex is shipped t o this country practically unchanged. Various substances (secret) are added to it to make it plastic, viscous, waterproof, and rustproof and t o color it. This liquid rubber is finding extensive use in industries which formerly required benzol-rubber solutions, or naphtharubber, especially for impregnating fabrics, or for cementing, or for producing hermetically sealed containers. PRESENT USE OF BEXZOILNINDUSTRY The National Safety Council listed as the chief benzol wing industriesin 1922: (a)rubber, especially tire building; (b) artificial leather manufacture; (c) sanitary can manufacture; (d) dry cleaning; (e) paints, varnishes, and stains-their use rather than their production. Let us take these industries in order and see what the situation is at the present day with regard to the use of benzol. Rubber Industries Rubber tire buiIding still employs benzol as a solvent for the cement, and large amounts are used. The risk is much greater for the tire builder than for the cement mixer; in fact, when mixing is properly carried on there is no escape of benzol vapor. But in tire building each layer of rubberized cord or cloth is painted over with benzol cement, and the tire is built up of many layers. The nature of the .1 work does not permit placing eshaust ventilation in such a position as to carry off all the dangerous fumes. It was in tirg building that Harrington's (6)five cases of benzol poisoning, with aplastic anemia and hcmorrhnges, occurred, a11 in mcn, all severe, and three fatal. Although benzol has not been displaced in tire building, there are other processes in tire making where latex is being introduced. Thus cord fabric is now made by drawing parallel cords through a bath of latex and drying them carefully in the proper spacing so that a sheet of fabric results in ,which the cords are held together by a wall of rubber. It is said also that inner tubes can be made from latex. Benzol is still used in making rubber cement for shoes and for fastening rubber heels on leather shoes, as can be seen from a recent article by Hunter and H d i g (7)describing six cases of benzol poisoning, three of them in shoe factory workers, and a fourth in a cobbler, all of whom used a cement containing a large proportion of benzol. Two were women, one of whom died; one of the men also died. Many shoe factories, however, have given up benzol cement and are using latex, for leather, for rubber and leather, and for fastening sole welting. In making spread rubber goods, impregnating fabric by pressing rubber dough into it and driving off the solvent by heat, benzol may be used, although apparently not often as a regular procedure; still it may be used from time to time as the market for the petroleum solvents varies and as benzol is for the time being more process which produccs almost invariably dangerous quantities of benzol -vanor. as the rubber dough is suread .I by mcans of a long, fised knife over the fabric which then passes on over steam pipes, to emerge from under a hood OF out from n chamber still n-arm and with some of the benzol still evaporab ing (8). That the escape of fumes is inevitable is seen from the high fire insurance rates imposed in such a plant. Even when naphtha is used, the work is unhealthful, and it is therefore a great advance in industrial hygiene to be able to substitute latex for rubber solution in m a h g spread rubber, as one of the largest firms in the country is already doing. Dipped rubber goods, such as surgical gIoves, may now be made from latex instead of rubber-benzol, as I have myself seen done, and we are assured that this use of latex will be greatly extended in the future. Artificial Leather Manufacture Artificial Ieather manufacture involves the use of great quantities of coating which, up to the present time, has always contained benzol.* In reading the reports of benzol poisoning in the literature it is often difficult to determine whether the victim was occupied in making artificial leather, fabrikoid, by spreading a coating on fabric, or in making patent leather by spreading a coating on skins. Essentially the two processes are the same, for in both the coating contains benzol. These new coatings, which are also used now as lacquers for d sorts of surfaces, consist of nitrocellulose dis- ' .? L i r . J 7 , : $I(:?-iIL 230 THE JOURNAL OF INDUSTRIAL HYGIENE solved in normal butyl acetate or Sanitary Can Manufaelure sometimes o. mixture of ethyl, amyl, and butyl acetates, together with normal butyl alcohol. Some oil, usually castor oil, is added as a plasticizer, and then benzol or toluol is added as thinner and solvent. Nor- mal butyl acetate would do the work alone, but it is much more expensive than the aromatics and therefore they are used up to the point at which they cease to act aa solvents and begin to precipitate the nitro cotton. At present lacquers used for spraying usually contain toluol, but for patent leather and artificial leather the more quickly evaporating benzol is preferred by many manufacturers, although some have given up benzol and are now using toluol because of its greater safety. Perhaps the most notorious source of benzol poisoning in American industry has been the manufacture of so-called sanitary cans for food products. Selling's (9) famous cases came from a Maryland factory making cans; so did McClure's (10); so did Hogan and Shrader's (11); and two which were reported to me personally in 19% came, one from Maryland, the other from the Pacific coast. Insurance men have assured me that for every case of benzol poisoning in the can industry. which came to light there were at least ten which remained unpublished. The fact that Maryland factories so often occupied the limelight was due not to worse conditions in these plants but t o the brilliant work of Selling of the Johns Hopkins The coating may be spread over the Hospital, which early called the atten- fabric in the same way that rubber is tion of Baltimore to this condition. spread, or it may be applied by a stiff These "sanitary cans" began some brush, or pressed into the leather with twenty years ago to take the place of a broad knife held slantingly. Neces- the former lead-soldered cans as sarily, in doing this hand work, the hermetically sealed containers for men must bend over the skin or "processed goods," i.e., cooked and fabric, and it is difficult to see how sterilized foods. They have several exhaust ventilation could be so placed advantages over the old type of can as to protect them efficiently, for it which required skilled solderers, whom is even difficult t o provide adequate it is diiEcult to find in the remote window ventilation without causing country districts where most canneries drafts of air which might deposit are situated. Moreover, the opening dust on the coating and spoil it. in the old type of can was at the most This is especially true of patent leather only 2 inches in diameter, and such where the slightest blemish shows. vegetables as tomatoes and sweet Two of Hunter and Hanflig's (7) potatoes had to be crushed to get them aiu cases contracted benzol poisoning in. The new can is made with ends in making patent leather, and in a which are the f d l diameter of the can, personal communication from New so that filling is greatly facilitated. Jersey (1927) I was informed of a Sealing is effected not by solder but fatal case in a man doing the same by clamping the end around the body work. of the can. Something, however, J. I. R. r I T t must be used to make it absolutely this industry seems to have under- &-tight. This can be done by a paper gasket if the contents of the can are somewhat liquid, for then the paper,awells and makes the joint tight. I saw paper gaskets in use in the great Dole pineapple cannery at Honolulu. They can also be used in canning tomatoes and corn, but not for drier foods such as spinach, beans, fish, nor for liquids. For these it has been customary to use a thin rubber cement made with benzol, a very fine stream of which is forced into the channel around the edge of the end piece, the gone a revolutionary change and benzol has been largely eliminated. This was brought about certainly in part by the earnest desire of some manufacturers to put a stop to the continually recurring cases of poisoning among the young women employed as takers-off, cases which appeared even in the best ventilated factories. The new sealing compound is rubber latex, and the rapid development of its use may be seen in the statement of a firm which produces sealing mixtures. Formerlythisfirmmadeforthe benzol being then driven offin a heated chamber and the end piece coming out with a thin band of the rubber in place. Since it is easier for canneries trade about 500,000 gallons of benzolrubber compound a year; now they make hardly 12,000,all the rest of their production being latex. to use one kind of can for all their Recently it was possible for me to products, there is not nearly so much visit five large can factories, belonging demand for paper gaskets aa for to three companies. In all but one of rubber-sealed cans, and the c a n making industry was, up t o two years ago, one of the largest consumers of benzol in the country. It was among the these, latex is used for sealing cans. The largest company in the country has adopted it altogether, the next largest has introduced it only partially, women and girls who received the can ends from the evaporating oven and inspected and stacked them while still warm that the cases of benzol poisoning developed.3 As recently as i' March, 1928, an article appeared in :, %IS JOGRNAL, by Adelaide Ross Smith (13), describing benzol poison: ing in women employed at such work, i- in three New York can factories. Among twenty-five women exposed to i!,.:-- benzol fumes, six showed evidence of :. chronic benzol poisoning. it.: During the last eighteen months still using in some branches a rubber solution, but not benzol. I n visiting these places it waa easy to see that contamination of the air with benzol fumes must have been inescapable even in the best factory, while in one where I found fifty-four coating machines closely crowded together in one rather low-ceiIed room, the situation must have been fraught with real danger. It is hardly an exaggeration to say that this change in sealing mixture means as great a reform in the large and growing can producing 7; t; . ... -. . . L r,; { -[.. .I t , b , -.-.4, . ._..i 2 . .,.. c , e. - ' : t. . * yf . ' r 133$: I . c. 8 , .- 5 :..`* 4I 1,`-. eE,.;'.; . %$3.;.-. p&;. ;.; * % ' *a; I' ' $y.? *. ` 232 THE JOURNAL OF lNDUSTRIAL HYClENE `41 effected by means of a rubber-benzol seen a change for the better, for much `a. mixture. of the lacquer now used for spray ft#&:j coating is made with toluol, and then . Dy Cleaning Indusfry ' is a strongeffort on the part of painters' Dry cleaners do not use benzol any organizations in such states as New more in Xew England. As to the rest York, Massachusetts, New Jersey, and of the country, I cannot speak with Wisconsin to prohibit the use of positiveness. I have a personal benzol in any coatings which an, to be communication concerning a woman applied by spraying. severely poisoned in a dyeing and cleaning establishment in Indiana, in HaiTcblh Manufacture 1927, but that is the only instance Another industry which deserves which has come to my knowledge in mention although it is not so important recent years. The fire hazard from as the others is the making of haircloth. benzol is great, leading to high i m r - Formerly a soiution of rubber in benzol ance rates, and naphtha is generally or naphtha wag used to bind the used in its place. The naphtha material together and prevent the selected has of late years been one of hairs from pulling out; now it is found the higher-boiling and less volatile that latex can be used for this purpose distillates, because the lower-boiling very successfully. fractions axe needed for motor car fuel. A still less volatile distillate, SUMMARY known as "Stoddard's Solvent" which The use of benzol in American ` distils between naphtha and kerosene, industry has markedly decreased in is beginning to make its way into dry the past six years and is still decreas- cleaning establishments, and, since it ing. Credit for this reform is largely is classed by the insurance companies due to the Kational Safety Council's after evaporation tests as no greater a investigation and the subsequent cam- risk than kerosene, it is evidently much paign of education among its members. lees volatile and therefore less toxic The greatest change is in the making than naphtha. of sanitary cans where benzol-rubber Paint Industries sealing compound is being rapidly replaced by rubber latex. Other occu- . The fifth important industry in the pations in which latex is displacing Kational Safety Council's list is the benzol-rubber are: making cord fabric dpainting trade, where benzol is added for tires, cementing shoes, both rub- aa a solvent and a thinner to paints, ber and leather, m-g dipped rubber 7%> varnishes, and stains, and is an and spread rubber goods. important constituent of paint and Toluol is displacing benzol in nit- 1varnish removers. Benzol evaporates cellulose coatings and lacquers, while : much more quickly than naphtha or naphtha, or the less volatile petroleum 4' even petroleum ether, and therefore is distillate "Stoddard's Solvent," hM? valued as a thinner for quickdrying largely displaced it in dry cleaning.: fpaints and for nitroceIIuIose lacquers. Several state organizations of the In this field also, recent years have painters' union have carried on SUC-6"~ BENZOL POISONING IN INDUSTRY 233 cessful agitation against the use of soles; for tire building; and as a benzol in quick-drying paints and constituent of paint and varnish other coatings. removers;but it is believed by insur- Benzol is still generally used for ance men and by many industrialists coating patent leather, and sometimes that in these processes also substi- i- artificial leather; for sealing bottles; tutes for benzol will eventually be for fastening rubber heels on leather found. BIBLIOGRAPHY For more complete bibliographies, the reader is referred to the Sational Safety Council report (1)and to Dr. Smith's article (13). F aqf .,u i ' . -tk 5. 1: FIru. ', 3 1. Final Report of the Committee on Benzol. Nat. Safety Council, hlay, 1926. 2. WINSLOW,C.-E. A.: Summary of the National Safety Council Study of Benzol Poisoning. THIS JOUR1.,927, 9,61. 3. BATCXELORJ., J.: The Relative Tox- icity of Benzol and its Higher Homologuea. Am. Jour. Hyg., 1927,7,276. 4. HEKTOEN, L.: The Effect of Toluene on the Production of Antibodies. Jour. Infect. Dis., 1916, 19, 737. See also KLINE, B. S., AND WINTER- NITZ, M. C.: Studies upon Experimental Pneumonia in Rabbits. V. The Rble of the Leucocyte in Experimental Pneumonia. The Relation of the Numbcr of Organisms Injected to the Mortality. Jour. Exper. bled., 1913, 18, 50. 6. Rubber Latex as 8 Non-Poisonous Substitute for Benzol Cements. N.Y. State Dept. Labor, Indust. Hyg. Bull., 1926,2,36;abstr. in THIS JOUR., 1927,9,30. 6. HARRINQTOTN., F.: Industrial Benzol Poisoning in Massachusetts. Boston Med. and Sura. Jour., 1917. 177.203. s.7. HUNTER, F. T.,AND HANPLIO, s.: Chronic Benzol Poisoning. Zbid., 1927,197,292. 8. CRONINH,.J.: Benzol Poisoning in the Rubber Industry. Ibid., 1924, f9f, 1164. 9. SELLINQL,.: A Preliminary Report of Some Cases of Purpura Hemorrhagica Due t o Benzol Poisoning. Bull. Johns Hopkins Hosp., 1910,U,33. 10. MCCLURE,R. D.: Pernicious Anemia Treated by Splenectomy and Sp- tematic, Often-Repeated Transfusion of Blood. Jour. Am. hled. Assn., 1916,67,793. 11. HOGANJ, . F., AND SKRADERJ,. E.: Benzol Poisoning. Am. Jour. Pub. Health, 1923,IS,279. c.:12. SPEIDEL, W. C., AND MELGARD, Purpura Hemorrhagic8 Following Benzol Poisoning. Northwest Med., 1925,Z4, 182. 13. SMITHA,. R.: Chronic Benzol Poison- ingamong Women Industrial Workers: A Study of the Women Exposed to Benzol Fumes in Six Factories. THIS JOUR., 1928,10, 73. Also N. Y. State Dept. Labor, Special Bull. So. 150,Feb.. 1927. . k'- m. 10 .No.7