An evaluation of chronic methylene chloride exposure.

Various groups including the Occupational Safety and Health Administration, Environmental Protection Agency, and Consumer Product Safety Commission have expressed concern over methylene chloride and its possible effects on human health. A group of employees exposed to relatively high levels of methylene chloride (average = 475 ppm 8-hour time-weighted average) for greater than 10 years were compared to a similar nonexposed group of employees for selected health parameters. All were participants in an employee health monitoring program. Selected questions evaluating cardiac and neurologic health effects revealed no differences between the two groups. Likewise, hematologic assessment also revealed no clinically significant differences between the two groups for SGOT(AST), SGPT(ALT), total bilirubin, and hematocrit. Therefore, it appears that chronic exposure to even high levels of methylene chloride produces no difference in symptoms or adverse health effects in this population as judged by selected liver, cardiac, and neurologic health parameters.