Mortality Study of Two Overlapping Cohorts of Photographic Film Base Manufacturing Employees Exposed to Methylene Chloride

Abstract

The mortality experience of two overlapping cohorts of employees engaged in the manufacture of photographic film support was evaluated to assess the potential chronic health effects of methylene chloride exposure. In the first analysis, we examined causes of death among 1311 men initially employed between 1946 (when the solvent was first used) and 1970; in the second, we updated mortality in a 1964 to 1970 employed cohort of 1013 men. Follow-up was through 1994. The mean exposure among members of the 1946 to 1970 cohort was 39 ppm (8-hour time-weighted average) for 17 years, and the median length of follow-up from first exposure was 34 years. Members of the 1964 to 1970 cohort received an average exposure of 26 ppm for 24 years; median time from first exposure was 35 years. Compared with general population vital statistics, mortality in both cohorts was below expectation for all causes of death, ischemic heart disease, and cancer, including such sites as the lung and liver, which were target organs identified in animal toxicology studies. No statistically significant increases were observed for any cause of death. The combined results of this study and three others in the photographic film and textile fibers industries (approximately 7300 subjects) show that long-term exposure to methylene chloride does not increase the risk of death from any cause including specific diagnoses that have been associated with this widely used solvent.

Update of a cohort mortality study of workers exposed to methylene chloride employed at a plant producing cellulose triacetate film base

“…The current investigation also provided no evidence of an increased risk of liver cancer or support for the excess of biliary cancer reported in one group of cellulose triacetate fibre workers (Lanes et al 1993). The excess of biliary cancer was not replicated in another highly exposed group of fibre workers (Gibbs et al 1996) or in the other cohorts of photographic film workers (Hearne and Pifer 1999). A suggestive excess of pancreatic cancer was reported in the first study of one of the cohorts of Rochester film workers, but Hearne and Pifer (1999) reported no new cases in the most recent update (8 observed and 5.3 expected), and there was no excess in the overlapping cohort of photographic film workers (5 observed and 5.5 expected).…”

“…The other cohorts include two overlapping cohorts of workers who were also exposed to methylene chloride during the manufacture of cellulose triacetate film base (Hearne and Pifer 1999) and two groups of workers who incurred exposure to methylene chloride in the production of cellulose triacetate fibres (Lanes et al 1993;Gibbs et al 1996). Table 7 of Hearne and Pifer (1999) summarises the exposure characteristics of workers in the different cohorts. The mean exposure of workers in the present investigation was 19 ppm compared with a workplace exposure limit in the UK of 100 ppm (8 h TWA).…”

“…The first study of the 1964-1970 Coating cohort by Hearne et al (1987) reported a suggestive excess of pancreatic cancer deaths (8 observed and 3.2 expected), but no more pancreatic cancer deaths have occurred in the cohort and the expected number of deaths has increased to 5.3 (Hearne and Pifer 1999). There was no excess of pancreatic cancer deaths in the second overlapping cohort, and compared with both the general population and a group of employed control subjects, there were reduced mortalities for lung and liver cancer and cardiovascular disease in both cohorts (Hearne and Pifer 1999).…”

“…Three of these groups of workers worked in plants producing cellulose triacetate photographic film base. Hearne and Pifer (1999) reported on the mortality experience of two overlapping cohorts of workers described as the 1964-1970Roll Coating and 1946-1970 Methylene Chloride cohorts, who were employed at a plant in Rochester, New York (44% of the total population were in both cohorts). Hearne et al (1987Hearne et al ( , 1990) also reported on the mortality experience of the 1964-1970 Roll Coating cohort, and two earlier studies reported on the mortality of the subset of employees who worked during 1964 (Friedlander et al 1978;Hearne and Friedlander 1981).…”

Two Offset Printing Workers with Cholangiocarcinoma

“…Other than the above study 1) , no cancer epidemiological study or cancer case report of 1,2-DCP exposed workers has been published. There have been four cohort studies of DCM exposed workers in two cellulose triacetate-film production plants 3,4) and two cellulose triacetate-fiber production plants 5,6) , but of these, only Lane's original study found a significantly increased mortality risk for biliary tract cancer 7) . Consequently, the association between these chemicals and cholangiocarcinoma should be studied further.…”