Abstract
A survey was conducted on a random sample of 30 out of a total of 140 dry cleaning plants operating in the City of Detroit and using petroleum solvents. Solvent in air concentrations were measured during various portions of the dry cleaning cycle and found to be below the proposed Threshold Limit Value of 200 ppm. The weighted exposure for a complete dry cleaning cycle was found to be 65 ppm for the solvent with a flash point of 105°F., 47 ppm for the solvent with a flash point of 120°F., and 25 ppm for a solvent with a flash point of 140°F. In Detroit, actual dry cleaning operations approximated four hours per 8-hour day. Accordingly, the weighted 8-hour exposure was 35 ppm, 25 ppm and 15 ppm respectively.
