Mortality study of two overlapping cohorts of photographic film base manufacturing employees exposed to methylene chloride

The mortality experience of two overlapping cohorts of employees engaged in the manufacture of photographic film support was evaluated to assess the;p otential chronic health effects of methylene chloride exposure. In the firs t analysis, we examined causes of death among 1311 men initially employed b etween 1946 (when the solvent was first used) and 1970; in the second we up dated mortality in a 1964 to 1970 employed cohort of 1013 men. Follow-up wa s through 1994. The mean exposure among members of the 1946 tr, 1970 cohort was 39 ppm (8-hour time-weighted average) for 17 years, and the median len gth of follow-up from first exposure was 34 years, Members of the 1964 to 1 970 cohort received an average exposure of 26 ppm for 24 years; median time from first exposure was 35 years, Compared with general population vital s tatistics, mortality, in both cohorts was below expectation for all causes of death, ischemic heart disease and cancer, including such sites as the I lung and liver, which were target organs identified in animal toxicology st udies. No statistically significant increases we-re observed for any cause of death, The combined results of this study and three others in the photog raphic film and textile fibers industries (similar to 7300 subjects) show t hat 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.