The control of perchloroethylene (127184) (PERC) exposure in commercial dry cleaning through ventilation was reviewed. Health hazards associated with PERC included central nervous system depression, liver and kidney damage, memory impairment, dermatitis, respiratory irritation, and other symptoms. Effective ventilation was considered to be one of the least expensive engineering measures for reducing worker exposures to PERC. Ventilation was used for controlling PERC exposures and thermal comfort, both of which were important in dry cleaning shops. Possible ventilation methods included local exhaust ventilation and general ventilation. Local exhaust ventilation (LEV) captured and removed the contaminant at or near the source of release, thereby reducing vapor levels in the worker's breathing zone and minimizing vapor diffusion. PERC vapor exposures were greatest during machine maintenance and loading and unloading. LEV implemented at the loading and unloading door was usually activated by a door interlocking system. The retrofitting of an external ventilation hood outside the machine door was an option for older machines lacking built in exhaust ventilation. General ventilation diluted the concentration of the contaminant before it reached the breathing zone of the worker. It was used to supply conditioned fresh air and exhaust contaminated air from the general work area. A workroom air exchange every 5 minutes involving sufficient volumes of make up air was recommended. Systems of emergency ventilation were needed to control solvent vapors resulting from solvent spills or leaks.