Factory workers, cancer development

Using a predictive model developed from mesothelioma data from studies of asbestos insulation workers (Peto et al. 1982), asbestos textile workers (Peto 1980), amosite factory workers (Seidman 1984), and asbestos-cement workers (Finkelstein 1983), EPA (1986a) estimated that continuous lifetime exposure to air containing 0.0001 f/mL of asbestos would result in about 2-3 cases of mesothelioma per 100,000 persons. The corresponding cumulative lifetime exposures associated with excess risks of 10 " -10 are shown in Figure 3-1. Cumulative exposure levels of 0.031, 0.0031, 0.00031, and 0.000031 f-yr/mL represent excess mesothelioma risks of 10" , 10 , 10, and 10 ", respectively. Appendix D provides further details on the derivation of these risk estimates. Currently (in 2001), EPA is in the process of reviewing their cancer risk estimates for asbestos fibers. 

Chronic skin exposure to turpentine may produce a hypersensitivity reaction, with bullous dermatitis and/or eczema. A case-control study of workers in particle-board, plywood, sawmills, and formaldehyde glue factories demonstrated a statistically significant association between chronic exposure (longer than 5 years) to terpenes (the principal component of turpentine) and the development of respiratory tract cancers. 

Coal Tar Products. An excess of breast cancer cases in St. Louis Park, Minnesota, was tentatively associated with coal tar contamination of the water supply (Dean et al. 1988). However, in a subsequent analysis of these data, the Minnesota Department of Health (1985) concluded that this study did not provide adequate evidence to associate breast-cancer with coal tar creosote-contaminated water (for a detailed discussion of these data, see Section 3.2.2.7 Cancer). No adverse effects on sperm characteristics were reported in male workers exposed to coal tar pitch volatiles in an industrial setting (Ward 1988). In addition, no adverse reproductive outcomes were detected in a survey of inhabitants of a housing development built on an abandoned creosote factory site, which was known to be contaminated with creosote (Agency for Toxic Substances and Disease Registry 1994). A retrospective study of dermal exposure to coal tar found no increased risk of spontaneous abortion associated with exposure to coal tar during pregnancy, but this was a small study and was unlikely to have sufficient resolution to detect a modest increase in risk (Franssen et al. 1999). 

The problem of bladder cancer in industry was identified following the clinical observation of an increased incidence of the disease in workers in particular industries. Further enquiry established that the affected workers were located in parts of the factory where exposure to a particular class of chemical occurred [7]. In due course, in this case some 60 years, these observations were confirmed and amplified by an epidemiological study showing that in the British chemical industry a high incidence of bladder tumors had developed in men exposed to benzidine, replacing suspicion by statistically significant evidence[9]. 

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