An evaluation of retrofit engineering control interventions to reduce perchloroethylene exposures in commercial dry-cleaning shops.
Earnest G; Ewers L; Ruder A; Petersen M; Kovein R
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana. Fairfax, VA: American Industrial Hygiene Association, 2001 Jun; :24
Air sampling and real-time monitoring were used to evaluate the ability of engineering controls retrofitted on two existing dry-cleaning machines to reduce worker exposures to perchloroethylene. In one dry-cleaning shop, a refrigerated condenser was installed on a machine having a water-cooled condenser to further reduce the machine air temperature, improve vapor recovery, and lower exposures. In a second shop, a carbon adsorber was retrofitted on a machine to adsorb residual perchloroethylene not collected by the existing refrigerated condenser to improve vapor recovery and reduce exposures. Both controls reduced the perchloroethylene exposures of the dry-cleaning machine operator. Real-time monitoring was performed to evaluate how the engineering controls affected exposures during loading and unloading the dry-cleaning machine, a task generally considered to account for the highest exposures. The real-time monitoring showed that dramatic reductions occurred in exposures during loading and unloading of the dry-cleaning machine due to the engineering controls. Peak operator exposures during loading and unloading were reduced by 60 percent (1 ,139.3 ppm to 456.4 ppm) in the shop that had a refrigerated condenser installed on the drycleaning machine and 92 percent (352.9 ppm to 29.4 ppm) in the shop that had a carbon adsorber installed on a machine with an already existing refrigerated condenser. Although loading and unloading exposures were dramatically reduced, drops in full-shift time-weighted average exposures were less dramatic. Time-weighted average exposures to perchloroethylene, measured by conventional air sampling, showed smaller reductions in operator exposures of 28 percent or less for both controls. Differences between exposure results from real-time and conventional air sampling likely resulted from other uncontrolled sources of exposure, differences in shop general ventilation before and after the control was installed, relatively small sample sizes, and experimental variability inherent in field research. This study showed that retrofit controls may be a feasible option for some shops to reduce perchloroethylene exposures, and bring machine operators into compliance with OSHA peak exposure limits.
Exposure-levels; Employees; Employee-exposure; Toxins; Air-sampling; Monitors; Monitoring-systems; Engineering-controls; Dry-cleaning-industry; Workers; Work-environment; Work-areas; Exposure-levels; Vapors; Hazards; Statistical-analysis; Exposure-limits
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana