Perchloroethylene exposure assessment among dry cleaning workers

Perchloroethylene (Perc), the most widely used solvent in dry cleaning, is toxic to the liver, kidneys, and central nervous system and may be a human carcinogen. In the Detroit area, as part of a project investigating the health status of dry cleaning workers, an exposure assessment was carried out in dry cleaning plants using perchloroethylene. Breath samples were obtained from each participant, and time-weighted average (TWA) breathing zone air samples were obtained using passive dosimeters on a subset expected to experience a range of exposures. Perc in breath and Perc in air were highly correlated (r2 = 0.75, p less than 0.0001). On average, operators of dry cleaning equipment experienced significantly more exposure than nonoperators. Also, employees working in shops that use transfer equipment (requiring physical transfer of Perc-saturated clothing from washers to dryers) showed significantly higher exposure than those in shops utilizing dry-to-dry machinery (permitting washing and drying in one machine in a single cycle). One or more air samples in every transfer shop exceeded the recently revised Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 25 ppm, while no air samples in dry-to-dry shops exceeded this limit. The results suggest concern for exposures to operators in transfer shops and that compliance with the PEL is achievable by engineering controls with presently existing technology.