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(1985): "The Job 1): "Reproductive ure. J Occup Med 'irie cohort study: 10:18-25. ons on Limits for tion Report: Preafety and Health, tionship between ihington DC: US 4f n DC: US hington DC: US lemaking, health thanol and their 1." Washington is in the Work- 2d 444 (DC Cir tion; a reassess- general illness tioner needs to iresented to the d 43:^ .i-552. >n: a review of ntal surgeries: nviron Health : Recognizing In Levy BS, d Diseases." Control 14: ol ethers on American Journal of Industrial Medicine 16:281-287 (1989) Mortality Among Employees of an Ontario Factory That Manufactured Construction Materials Using Chrysotile Asbestos and Coal Tar Pitch Murray M. Finkelstein, PhD mdcm This paper describes mortality in a cohort of 324 men exposed to chrysotile asbestos and coal tar pitch used in the manufacture of electrical conduit pipe from a mixture of newsprint, bentonite, and asbestos. One death in a factory worker was attributed to pleural mesothelioma, and long-term employees experienced an increased risk of lung cancer (Standardized Mortality Ratio (SMR) 221; six deaths) and non-malignant respi ratory disease (SMR 215; four deaths). In a case-control analysis, men whose jobs involved adding asbestos to the mix of raw materials were found to have a risk of lung cancer sevenfold higher (lower 95% confidence limit: 2.3) than men who had never worked at this job. Exposure to coal tar pitch is presumed to be responsible for the death of one worker from squamous cell carcinoma of the scrotum. Key words: lung cancer, mesothelioma, cancer of the scrotum INTRODUCTION Studies of asbestos-exposed workforces have generally found that the risk of asbestos-associated diseases depends on the nature of the work activity and the variety of asbestos mineral used. As examples, the manufacture of friction materials con taining chrysotile asbestos appears to carry relatively low risk [Berry and Newhouse, 1983], while the manufacture of crocidolite-containing gas masks was a very highrisk activity [Jones et al., 1980]. Regulatory authorities in Europe and Canada have responded to the apparent differences in the toxicity of the various asbestos minerals by adopting differing regulatory standards for them. As a result, the use of the amphibole minerals amosite and crocidolite has effectively been eliminated, and chrysotile asbestos has become the sole asbestos mineral of any importance in com merce. The results of a mortality study of workers exposed to chrysotile asbestos in an Ontario manufacturing plant are presented here. This study came about because a former employee of the factory contacted The Royal Commission on Matters of Health and Safety Arising From the Use of Asbestos in Ontario to express the concern Health Studies Service, Ontario Ministry of Labour, Toronto, Canada Address reprint requests to Murray M. Finkelstein, PhD, MDCM, Health Studies Service, Ontario Ministry of Labour, 400 University Avenue, 8th Floor, Toronto, Ontario, Canada M7A 1T7. Accepted for publication February 23, 1989. 1989 Alan R. Liss, Inc. 284 Finkelstein TABLE II. Mortality Ratios According to Cause of Death, Length of Employment, and Time Fropi First Employment in an Ontario Pipe Factory Years since first employment Diagnosis 10-19 years 20-29 years >30 years Total a20 Length of----------------------------------------------------------------------------------------------- employment OBS EXP SMR OBS EXP SMR OBS EXP SMR OBS EXP SMR All causes 1-9 years 4 3.56 110 All causes 10 years or more 5 6.13 82 All cancer 1-9 years 0 0.78 0 All cancer 10 years or more 2 1.20 170 Lung cancer 1-9 years 0 0.25 0 Lung cancer 10 years or more 0 0.35 0 GI cancer 1-9 years 0 0.17 0 GI cancer 10 years or more 1 0.31 320 Respiratory Dis. 1-9 years 0 0.14 0 Respiratory Dis. 10 years or more 1 0.25 400 Ischemic heart 1-9 years 3 1.17 260 Ischemic heart 10 years or more 1 2.43 41 2 3.88 52 14 15.1 93 0 1.05 0 5 3.63 138 0 0.38 0 3 1.24 242 0 0.22 0 0 0.85 0 0 0.18 0 2 0.83 240 0 1.26 0 4 5.96 67 0 0.17 0 26 15.8 165 0 0.05 0 7 4.17 168 0 0.02 0 3 1.48 200 0 0.01 0 2 0.92 220 0 0.01 0 2 1.03 190 0 0.06 0 8 6.00 133 2 4.05 49 40 . 30.9 129 0 1.1 0 12 7.8 154 0 0.40 0 6 2.72 221 0 0.23 0 2 1.77 110 0 0.19 0 4 1.86 215 0 1.32 0 12 12.0 100 OBS, number observed; EXP, number expected. GI, cancer includes esophagus, stomach, and bowel ICD: 150-154, ninth revision. Respiratory diseases includes International Classification of Diseases (ICD): 480-519. Ischemic heart disease includes ICD; 410-414. the attention of physicians. It was not possible to confirm the diagnosis because the pathologic material could not be located for review. No deaths occurred during the period of follow-up among the men who had been employed for less than 1 year; three deaths would have been expected according to Ontario mortality rates. The mortality pattern among the men who were employed 1 year or more is given in Table II, stratified according to time since first employment. Omitted from Table II are the three deaths that occurred in the cohort within 10 years of hire; two were due to non-occupational trauma, and one was due to tuberculosis. The mortality pattern among the men who were employed less than 10 years is unremarkable. No deaths from cancer or respiratory disease were found 20 or more years after first employment, but this subcohort is so small that only one cancer death would have been expected. The men who were employed 10 years or more were found to have elevated mortality rates from cancer and respiratory diseases. The period following 30 years from first employment saw substantial excess mortality, with deaths from cancer, respiratory disease, and ischemic heart disease contributing to the surplus. In addi tion, there were four traumatic deaths where 0.7 would have been expected. Cigarette smoking is a major cause of both lung cancer and respiratory disease and thus is a potential confounder of the relationships between occupational expo sures and disease. Smoking information was not generally available for the members of the cohort. A survey was carried out, in 1983, of individuals who were employed at the time of plant closing; 80 responses were obtained. Eighteen individuals, 23% of those replying, claimed never to have smoked. Eighty-six percent of the 37 men 45-64 years of age were or had been smokers, in comparison with a prevalence rate of 75% in the Ontario Labor force in 1983 [Department of National Health and Welfare, 1985]. T\ period 2 skin of t operator the ster squamoi well kn< lymphoi research life, it i; Case-C Ha among t attempt man dy; lected fr (with a i the case Lv diagnosi and four specime Th respect occupati operator worked likelihov beater c operatoi victims Ui the 6 m enginee was of l be reme Nc on the c sure to. years in in com( year of disease The ass disease the 4 m ntrol had worked respiratory dis used chrysotile control analyses employment as witness as being *arette smoking >re likely to b ;ht account fo ver, that then occupationa : `he associ-08]. ds of workers mortality of knowing how ght compare this cohort, from two Data Base at rocedure, and an underes- an the death underestimate Plant, so that exposures to 'perators who is, these confidence man who prior to the material hazards of sed to coal bility that interaction men who directly nufacturing cohort: one otum. It is Mortality in a Chrysotile Asbestos Factory 28` disheartening that, 200 years after the first descriptions of scrotal cancers as occu pational diseases, deaths are still occurring from this tumor. REFERENCES Berry G, Newhouse ML (1983): Mortality of workers manufacturing friction materials using asbestos. Br J Ind Med 40:1-7. Coleman M, Douglas A, Hermon C, Peto J (1986): Cohort study analysis with a Fortran computer program. Int J Epidemiol 15:134-137. Department of National Health and Welfare (1985): Smoking Habits of Canadians, 1983. Ottawa: De partment of Supply and Services (Cat. No H39-66/1985E). Finkelstein MM (1984): Mortality among employees of an Ontario asbestos-cement factory. Am Rev Respir Dis 129:754-761. Howe G, Lindsay J (1981): A generalized iterative record linkage computer system for use in medical follow-up studies. Comput Biomed Res 14:327-340. Jones JSP, Smith PG, Pooley FD, Berry G, Sawle GW, Aggarwal A, Wignall BK, Madeley RJ (1980): The consequences of exposure to asbestos dust in a wartime gasmask factory. In: "Biological Effects of Mineral Fibres," Vol 2, IARC Scientific Publications No. 30. Lyons: International Agency for Research on Cancer, pp 637-653. Siemiatycki J, Wacholder S, Dewar R, Wald L, Begin D, Richardson L, Rosenman K, G6rin M (1988): Smoking and degree of occupational exposure: Are internal analyses in cohort studies likely to be confounded by smoking status? Am J Ind Med 13:59-70. Storer B (1983): PECAN Statistical Software. Seattle: University of Washington, Department of Biosta tistics.