Abstract:
This study evaluates occupational exposure to perchloroethylene (PCE) among commercial dry cleaning workers (n=72), typically in small businesses with fewer than 15 employees. No eligibility restrictions were imposed on volunteers according to sex or age; but, shops currently not using PCE were excluded. Two processes characterize this business, wet transfer shops where solvent laden clothes are manually loaded into a dryer (approximately 70% of commercial dry cleaners) and dry-to-dry shops where cleaning and drying occur in the same machine.
Relationships between three perchloroethylene exposure measures were examined: personal dosimeter (3M #3500) sample concentrations were ranged from 0.20 - 85.64 ppm, expired alveolar breath concentrations (normalized to 5% CO2) which ranged from 0.37 - 22.23 ppm, and peak (37.0 - 423.0 ppm) and mean area concentrations (0.90 - 56.34 oom) which were determined using a Bruel and Kjaer 1302 gas monitor. This instrument enabled collection of two minute area samples throughout the day within 10 feet of the worker.
Regression analyses were performed between personal dosimeter and mean area concentrations (r= 0.88, p< 0.0001), and between both air measurements and perchloroethylene concentrations in breath sample (area: r= 0.85, p< 0.0001; personal dosimeter: r= 0.84, p< 0.0001). Analysis of variance determined that process (wet transfer or dry-to-dry) and job title exerted a strong effect on all measures of exposure. Until now, variation in exposures throughout a work day has not been well characterized. On average, wet transfer operator were found to spend 14.7% of their shift exposed at concentrations above 50 ppm PCE (2 times the PEL), whereas dry-to-dry operators were exposed to this level only 0.65% of their shift. Housekeeping practices had a highly variable, but potentially large impact on exposure. Season of testing had a marginally significant impact on exposure. No significant association was found between exposure and gender. Wet transfer operator exposures significantly exceeded dry-to-dry exposures, with unacceptably high peak concentrations (up to 423 ppm). Both afternoon and morning post-exposure breath concentrations of PCE appeared to be good biological markers of ambient exposure concentrations.