The ability of a vapor recovery system to control occupational tetrachloroethylene (127184) exposures during dry cleaning was evaluated. The study was conducted in a commercial dry cleaning shop which used a dry/to/dry dry cleaning machine for its operations. The machine was fitted with two independent vapor recovery systems. The primary system was a refrigerated condenser that operated during the dry cycle. The secondary system consisted of a fan directed to a canister containing activated charcoal. The fan was activated whenever the machine door was opened. Area and personal air samples, collected on three of six employees, were analyzed for tetrachloroethylene by gas chromatography with flame ionization detection. Additional personal air samples were collected in real time and analyzed for tetrachloroethylene by a photoionization detector. The personal time weighted average (TWA) tetrachloroethylene exposures of the three workers varied from 13.2 to 18.6, 2.2 to 6.5, and 1.4 to 3.0 parts per million (ppm). The mean TWA exposures were 15.8, 4.9, and 2.5ppm, respectively. The machine operator had the highest TWA exposure. Geometric mean (GM) area tetrachloroethylene concentrations measured behind and above the machine varied from 4.7 to 9.7ppm. The GM area tetrachloroethylene concentration in the reception area was 2.3ppm. All exposures were below the current OSHA standard, 25ppm. Real time monitoring indicated that tetrachloroethylene exposures associated with loading and unloading the dry cleaning machine averaged 846 and 271ppm, respectively. Tetrachloroethylene concentrations as high as 1,500ppm were measured near the carbon canister whenever the machine door was opened, indicating that the canister was ineffective in capturing tetrachloroethylene. The author concludes that controls in this dry cleaning shop maintain TWA tetrachloroethylene exposures below 25ppm. Loading and unloading the dry cleaning machine produces very high transient tetrachloroethylene exposures. Modifying the secondary vapor recovery system or using exhaust ventilation would dramatically reduce tetrachloroethylene exposures during loading and unloading.