Methylene chloride is partially metabolized to form
carboxyhemoglobin, the probable result being a reduction in oxygen availability to the myocardium. Thus, among exposed individuals, there could be a potential for an increased risk of ischemic events, particularly among those with advanced coronary artery disease. The present retrospective cohort study focused on ischemic heart disease deaths among employees of a fiber production plant in which methylene chloride was used as a general purpose solvent. The range of methylene chloride exposure was a time-weighted average of approximately 140-475 ppm. In comparison to the mortality of the general population of the United States, there was no significant increase in overall mortality or in deaths due to ischemic heart disease. Further analyses of ischemic heart disease mortality by employment status, duration of exposure, and follow-up interval did not reveal any exposure-related effect either. Thus, given qualifications relative to statistical power and possible confounding bias (eg, healthy worker effect) attendant with this study, no mortality effects attributable to methylene chloride exposure were found.

Key terms death; employee; health evaluation; ischemic heart disease; methylene chloride; mortality; occupational exposure