Document OdoLDogOroaBd5JprJKyOVbw

FILE NAME: Goodyear (GY) DATE: 1949 Nov DOC#: GY104 DOCUMENT DESCRIPTION: Journal Article - Study of Workers Exposed to Talc & Other Dusting Compounds in the Rubber Industry BC Notes: 1949 Published report by Hogue and Mallette, "A Study of Workers Exposed to Talc and Other Dusting Compounds in the Rubber Industry," referencing 1942 and 1943 reports on NY talc miners by Porro and Siegal et al. (JIHT31: 359-364, 1949) [vol. 31, no. 6 i t poison with .tic, renal and adiiy through ration should shere, and no ermitted. thylene chlor- immended for ed continuous a chamber is main on" dur- ldude medical ils. :r, C. P.: Note chlorhydrin by 945. Suggestions for ydrin treatment ntly harvested apson Institute, Benny, F. E.: rates and time itemal factors, 41-61, 1936. three chemicals otato tubers to ns of the Boyce uly-Sept. 1945. A STUDY OF WORKERS EXPOSED TO TALC AND OTHER DUSTING COMPOUNDS IN THE RUBBER INDUSTRY* * W arren L. H ogue, J r . and F rederick S. M allette Firestone Tire and Rubber Company, Akron, Ohio T ALC and similar minerals are widely used in industry. In the Mineral Yearbook Johns ton and Barsigian (1) report that in 1946 over 450,000 short tons of domestically produced talc, pyrophyllite, and ground soapstone were consumed, of which 77 per cent was utilized in five industries--paint, rubber, roofing, ceramics, and insecticides. The paint industry alone used 23 per cent of the total. 1,440 million particles per cubic foot in pneumatic drilling operations and as low as 4 million outside the mill proper. He reported that "in only three cases (5%) were the X-ray findings within the limits of normal; 38 (6 1 %) showed evidence of an early or first-stage pneumoconiosis." Only one case--that of an individual who had been in the tremolite mills for over 40 years--had fibrosis advanced beyond the first stage. Dreesen con Chemical Composition cluded that the resulting pneumoconiosis was not disabling. One should note that the above-mentioned re port groups talc with materials of like commercial applications rather than with those of mineralogical or chemical similarity. Actually talc is a hy drous magnesium silicate with the formula M gy S40 io(OH)2. Other minerals which have similar uses are: pyrophyllite, a hydrous calcium mag nesium silicate, Ca2Mg5Sig(OH)2; serpentine, a hydrous magnesium silicate, MgaSi20 7 (0 H)2; and dolomite, a calcium magnesium carbonate, CaMg(COj)2. Tremolite, frequently found in nature with talc, has a fibrous variety which is used to some extent as asbestos (2). Soapstone is the granular to cryptocrystalline form of talc. In 1935 Dreesen and Dalla Valle (5) reported dust concentrations varying from 32 to 1,672 million particles per cubic foot in two Georgia mills. Among 66 workers examined, they found 8 having advanced pneumoconiosis with disabil ity and 14 having roentgenographically demon strated slight pneumoconiosis without disability. The dust was found, by analysis, to consist chiefly of soapstone, but it also contained 10 per cent tremolite. The authors stated that the dust of the Georgia mills appeared to be more injurious than that reported by Dreesen (4). However, the study made in Georgia showed much higher concen trations of the dust. Furthermore, quite a few of Apparently the physical characteristics of all these materials are so much alike th at they may be used in almost identical applications and there fore are designated commercially as talc. Schulz and Williams (3) pointed out that "talc as used industrially generally refers to a substance which meets certain physical requirements rather than one which has a definite chemical composition." In an examination of 71 analyzed samples they found extreme variation in composition. the miners had worked in hard rock, although only 6 out of 13 showed pneumoconiosis stage I. Eason, Trice, and Carpenter (6) reported pul monary fibrosis among miners and millers of pyrophyllite, characterized roentgenographically by massive tumor-like shadows bilaterally situated in the subapical region or by granular densities distributed throughout the lungs. Of 101 workers, 35 per cent of those with two or more years of exposure showed evidence of pathologic changes P hysiological E ffects in the lungs. The pyrophyllite dust contained from 25 to 35 per cent quartz. In general, most silicates of this kind were con Porro, Patton, and Hobbs (7) found 15 cases sidered harmless until 1933 when Dreesen (4) of pneumoconiosis in two tremolite mines- and studied conditions in tremolite mines and mills. mills in New York State. According to them, the He found dust exposures averaging as high as composition and concentrations of the dust were , Presented at the Annual Meeting of the American industrial Hygiene Association, Detroit, Michigan, April 5-8, 1949. the same as those reported by Dreesen (4), who had previously surveyed one of the plants. Non disabling pulmonary fibrosis was found in almost 359 Material may be protected by copyright law (Title 17, U.S. Code) 360 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [vol. 31, no. 6 all of the workers examined. Of the IS patients, 7 Were known to have worked in other types of mining operations. Dyspnea was an almost uni versal complaint, and several patients had cyano sis and club fingers. In all of those tested with a spirometer, vital capacity was very low (35-52 per cent). In the 5 postmortem examinations asbestosis bodies were a fairly frequent finding in lesions of the lungs. This may not be puzzling when it is recalled that tremolite is characteris- talc (in the past, to pyrophyllite) were those of refiner operators, strainer operators, mill men, truckers, slab checkers, and shipping laborers. The results of the surveys have been averaged for the period 1943 to 1948 and are presented, together with the number of years of total expo sure of the various occupations, in tables 1 and 2. I t must be emphasized that before the installation of control ventilation the dust concentrations were probably much higher. tically fibrous. _ Further studies in tremolite mines and mills of northern New York by Siegal, Smith, and Green- burg (8) disclosed 32 cases of advanced fibrosis in a group of 221. Dust counts in the mines varied from 6 to 5,000 million particles per cubic foot in milling. The talc was of the asbestine variety and was mingled with tremolite and anthophyllite. The fibrosis tended to be disabling and was fre quently accompanied by dyspnea, cough, and fatigue. Prompted by these reports and by proposals TABLE 1 Average D ust Concentration and P eriod or E xposure for Workers in T alc _____ WOEKEBS EXPOSED YEAB3 OF EXPOSURE M IL L IO N S OF FASTIC L E S /C U . FT. 20-34 20 0 l U D v Q l a U l i i i O /uVpTlvATi ial twn ri os . .. .. .. .. . . 1 4-*'*Vu . . ............................... 32-36 35 10-34 15 14 50 for the inclusion of a limit for talc among dust hazards in certain state codes (9, 10, 11) we made a study in two rubber plants where workers had been exposed to talc and other dusting compounds for periods as long as 36 years. Talc dusting ex periments were made on laboratory animals, the results of which will be reported in a separate f TABLE 2 Average D ust Concentration and Period of E xposure for Workers in Whiting, P vroPHY.HTE, AND TALC W&SEES EXPOSED YESS O f EXPOSURE m il l io n s Of P A S T Ic l e s / ctj. FT. communication. 1*9 r e x n i c r A nfil'otftTSS ............................................. 13-25 50 D usting R ubber o strainer o p c i a v u i a ..................... 15-25 75 As rubber is naturally tacky, it must be coated 24 50 with a lubricant to keep it from sticking together. 1 trucker.................................. 2230 3500 Many materials are used, both in the wet and the 24 150 dry state, for this purpose. Among them are talc, 1 s n i p p i n g i d w i o i ........................................ pyrophyllite, mica, clay, walnut shell dust, com starch, whiting, et cetera. Operations employing these materials in the dry state tend to be very dusty. In recent years control ventilation has reduced the concentrations of the dusts, but there are still operations, especially of an intermittent or temporary nature, which it is difficult or im practical to control. In these operations dust respirators must be relied upon for protection. For the past six years periodic dust surveys have been made of several processes in the manu facture of inner tubes and in the reclaiming of rubber. The occupations in which talc was the only dust to which workers were exposed were those of tuber operators, tube bookers, tube cure men, and liner rerolling. Those jobs in which the major exposure was to whiting and the minor to D ust Composition The dusting compound used in the tube opera tions and in rerolling liners is a pure talc from a deposit near Johnson, Vermont, and contains no free silica, tremolite, chrysolite, chrysotile, or actinolite. It has the following composition: Talc Analysis Silicon dioxide....................... Ferrous oxide...................: Aluminum oxide..................... Manganese oxide.................. Sodium oxide.......................... Potassium oxide..................... Combined water.................... Carbon dioxide....................... 34.86% 6.30 1.22 0.09 0.53 Trace 6.17 15.10 Material may be protected by copyright law (Title 17, U.S. Code) Nov. 1949] TALC DUST EXPOSURES 361 Whiting (calcium carbonate) is the principal compound for dusting reclaimed rubber. Until about six years ago pyrophyllite containing 65 per cent free silica was used for certain stocks, but since that time talc has been used for these special applications, but the use of both compounds amounted to only about 10 per cent of production. C linical I nvestigation The two groups of workers included in this study were specially selected for type and length of exposure. Only those with the longest and heavi est exposures were included. Complete physical posed of 20 men who had been exposed to talc alone for periods ranging from 10 to 36 years. All of the men were working at the time of the study and were in apparent good health. None of them presented any symptoms referable to the lungs, such as dyspnea, cough, or shortness of breath. None had clubbing of the fingers or cyanosis. Only one member of this group had subnormal (71 per cent) vital capacity. This finding can perhaps be explained by the presence of an enlarged heart, as determined by the Hodges-Evster formula. In this group the roentgenographic findings were either completely normal or showed only TABLE 3 Physical E xamination, Vital Capacity D eterminations and Chest R oentgenograms on Workers E xposed to T alc WORKER AGE YEARS OF EX POSURE M ILLIONS OF PA RTC LES/C U . FT. BLOOD PRESSURE V IT A L CAPACITY HEART CHEST ROENT GENOGRAMS REMARKS 117R 62 25 118R 62 30 119R 53 24 126R 49 31 908R 53 25 251R 50 30 196R 53 20 167R 62 36 187R 49 30 205R 49 32 186R 49 25 246R 51 10 209R 47 32 207R 52 31 17R 58 27 287R 50 24 206R 57 34 290R 43 14 292R 51 19 286R 39 18 20 144/92 86% -- 35 152/80 105% -- 20 112/68 119% + 10 Negative a u Coal miner--10 years 35 132/78 122% -- Li 20 142/82 71% + 17 u 15 142/80 112% -- u 20 160/90 94% Normal u 35 120/80 95% U u Coal miner--11 years 15 140/70 94% -- u 15 130/80 118% -- u 15 124/90 107% -- u 15 110/70 121% -- a 15 95/65 86% -- " 15 112/80 102% Normal u 15 140/95 118% -- a 20 138/78 116% Normal " Coal miner--15 years 20 194/94 85% -- a 50 104/71 105% -- a 15 110/65 93% -- a 15 120/55 114% -- u examinations, including blood counts, urinalysis, blood pressure readings, and vital capacity deter minations, were made. For the latter tests the Scott-McKesson apparatus was employed, and readings below 85 per cent were considered indica tive of disease of the heart or the lungs. Roent genograms of the lungs were made on 14" X 17" films and interpreted by a qualified radiologist with considerable experience in the diagnosis of pneumoconiosis. T ube W orkers Physical and Roentgenographic Examinations The first group, presented in table 3, was com- the chronic changes found in industrial urban dwellers. (See figure 1.) R eclaiming R ubber W orkers Physical and Roentgenographic Examinations The second group, presented in table 4, was composed of 20 men with a major exposure to whiting and minor exposures to pyrophyllite and talc. The exposure periods of this group ranged from 10 to 25 years. All of these men were also working at the time of the study, and none complained of or presented symptoms referable to the lungs, such as dyspnea, cough, or shortness of breath. No clubbing of the fingers nor cyanosis was noted. Material may be protected by copyright law (Title 17, U.S. Code) F ig. 1. This man is 62 years old and has worked in the rubber industry for 36 years w ith an average talc exposure of 35 million particles per cubic foot. His vital capacity was 95 per cent. These lungs show only truncal accentuation of the lower lobes. ' TABLE 4 P hysical E xamination, Vital Capacity D eterminations and Chest R oentgenograms on W orkers E xposed to Whiting, Pyrophyllite, and T alc WORKER AGE ! j Ef Y E A R b F POSURE i M ILLIONS OF PA X TI- ! C LES/C U . FT i BLOOD PRESSURE ! VITAL j CAPACITY HEART . CHEST ROENT GENOGRAMS REMARKS 229R 244R 228R 953R 55 23 62 | 15 47 24 49 195R 51 23 226R 59 24 248R 54 10 170R 42 13 165R 49 20 18L 48. 20 185R 64 18 247R 54 20 234R ; 54 23 231R 53 23 232R 55 25 164R 61 14 184R i 55 25 235R 55 24 217R 57 20 972R 55 23 50 160/100 71% + 17 Negative 0 158/86 60%* +25 i 1 Previously coal miner 50 104/56 85% Normal it 150 132/90 68% U Pneumonocon- Coal miner--5 years iosis III 50 124/90 116% -- Negative 50 140/70 99% -- it 75 130/90 90% Normal U 50 120/70 123% u 50 130/80 73% l i u 50 112/62 110% -- (( 50 180/98 101% + 10 u 50 160/85 119% Normal a 75 120/70 110% -- a 50 132/80 97% -- d 50 130/70 74% + 21 u 50 142/95 97% Normal iC 75 110/65 106% -- i i 50 175/100 94% -- i i 30 165/95 94% Normal it Coal miner--13 years Foundry--7 years Coal miner--4-j- years j Coal miner--19 years 50 i 182/120 56%t U * The subject was unsatisfactory--uncooperative, f The subject was 5 feet 2) inches in height and weighed 203 pounds. 362 Material may be protected by copyright law (Title 17, U.S. Code) Nov. 1949] TALC DUST EXPOSURES 363 Six hud vital capacities considered subnormal; of these, 3 had enlarged hearts, as determined by the formula mentioned above. In this second group only one chest roentgeno gram showed abnormality, which was considered third-stage pneumoconiosis. The man also had lowered vital capacity, but he appeared to be suf fering no disability. He had previously worked in the mining industry for five years. (See figure 2.) exposures restricted to that mineral. In the New York mines and mills the dust was composed of equal proportions of tremolite and talc. Porro cl al ii) published illustrations contrasting the fibrous structure of tremolite with the granular nature of talc. In the Georgia studies the dust was prin cipally soapstone, a form of talc, bu t also con tained 10 per cent tremolite. The dust in the N orth Carolina studies was not talc but pvrophyllitc and, Fig. 2. This man is 49 years old and has been employed in the rubber industry for 24 years with an average exposure to pyrophyllite and whiting of 150 million particles per cubic foot. He worked in coal mines for a period of five years. His lungs show well-advanced pneumoconiosis diagnosed as grade III. His vital capacity was 68 per cent. In spite of the well-advanced pneumoconiosis and lowered vital capacity, he showed no disability. His work record shows that he has lost only three weeks from illness over the past 24 years. Another group of 16 men engaged in the same rubber processes but with shorter exposure periods were examined in the same manner. All chest roent genograms were normal. The producer of the talc discussed in this study stated that periodic roentgenographic examina tions among his employees have failed to reveal any changes due to talc (12). D iscussion Previous publications reporting talc as a cause of disabling pneumoconiosis do not present furthermore, contained from 25 to 35 per cent quartz! In an excellent discussion of the entire m atter Pendergrass and Robert (13) stated " . . . the occurrence of an asbestosis-like reaction following prolonged exposure to talc would seem unlikely. Further controlled investigation, designed to elim inate the possible complicating factors of quartzcontaminated dust and infection, is, however, imperative before concluding with finality that the roentgen changes are the reflection of a specific and progressive fibrosis, and that talc is the sole Material may be protected by copyright law (Title 17, U.S. Code) 364 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY \vol. 31, no. 6 etiologic agent in their production. In this regard, it seems quite probable that the described coex istent noclulation may be silicotic in origin. In the reported autopsy cases there had been other opportunities for the inhalation of dusts presum ably contaminated with silica, and in the mining of talc itself similar exposures have not been ex cluded." Summary axd Conclusions 1. A review of the literature indicates that dust exposures producing pneumoconiosis allegedly due to talc were not restricted to th at mineral alone, as tremolite, pyrophyllile, and even quartz were also involved. 2. .Physical examinations and chest roentgeno grams of a group of 20 men exposed to talc dust (hydrous magnesium silicate) for periods ranging from 10 to 36 years in rubber inner tube produc tion were normal for men of their age; group and urban industrial environment. 3. Similar examinations of another group of 20 men exposed for periods ranging from 10 to 25 years to whiting (calcium carbonate), with minor exposures to pyrophyllite (65 per cent quartz) and to talc, in rubber-reclaiming operations dis closed all to be normal except one whose condition was diagnosed as pneumoconiosis stage III. This man had the highest dust exposure in the two groups (150 million particles per cubic foot) and had a previous occupational history of five years in mining. 4. The findings of the present study indicate that long exposure to talc does not appear to produce pathologic changes in the lungs. 5. Proposals th at limits for silicate minerals be added to lists of maximum allowable concen trations should include careful definition of chem ical and mineraiogical composition. REFERENCES (1) J ohnson, Bertrand L. and Barsigian, F. M.: Talc and Pyrophyllite. Minerals Year Book 1946, Bureau of Mines, United States Depart ment of the Interior. (2) D ana, J. D .: Manual of Mineralogy, revised by C. S. Hurlbutt, 15th Edition, John Wiley and Sons, Inc., New York, 1941. (3) Schulz, R. V. and W illiams, C. R .: Commercial talc: Animal and mineraiogical studies. This J.. 24: 75-79, 1942. (4) D reesen, W. C .: Effects of certain silicate dusts on the lungs. This j., 15: 66-78, 1933. (5) Dreesen, W. C. and D alla Valle, J. M .: Effects of exposure to talc in two Georgia talc mills. Public Health Reports, 50: 131-143, 1935. (6) E ason, H. F., T rice, M. F. and Carpenter, C. C .: A Study of Effects of Mining and Milling of Pyrophyllite. North Carolina State Board of Health, Division of Industrial Hygiene, and North Carolina Industrial Commission, Raleigh, North Carolina, 1939. (7) Porro, F. W., P atton, j . R. and H obbs, J r., A. A.: Pneumoconiosis in the talc industry. American Journal of Roentgenology and Ra dium Therapy, 17: 507-524, 1942. (8) Siegal, W illiam, Smith, A. R. and Greenburg, Leonard : Study of Talc Miners and Millers in St. Lawrence County. New- York State Indus trial Bulletin, vol. 22. November, December, 1943. (9) Preliminary draft, Proposed Ohio Industrial Pub ' lie Health Hazards Code, Ohio Department of Health, 1946. (10) Proposed California Safety Orders, as amended, Division of Industrial Safety, California Depart ment of Industrial Relations, August 23, 1948. (11) Tentative Hygiene and Sanitation Standards, Hygiene and Sanitation Section, Division of Engineering and Safety, Trenton, New Jersey. November 15, 1945. (12) Personal communication, W. W. Magnus, Eastern Magnesia Talc Company, Burlington, Vermont. (13) Pendergrass, E. P. and R obert, A. G .: Some considerations of the roentgen diagnosis of silicosis and conditions that may simulate it. Radiology, 50: 736-745, 1948. HIG The effec of tin dustriai hy Thomas ai tration cur of guinea bromide a: Recently, . need for lc pathologica mended th; of toxicity, logical stuc establishing daily expost time-concen Briefer e: contaminan in industria tions. Frequ from the co: In aviation, because pas: airplane uni the safety o. pends upon air crew. Th aviation ext responsibility Extinguish hydraulic fit which may l carriers cons logical stress insure the cc air crew in pheric contai detailed knot to exposure. 1 Presented Council, New Received foi *The opinio; are those of th as necessarily j of the Civil Ae Material may be protected by copyright law (Title 17, U.S. Code)