HETA 92-0360-2372 NIOSH INVESTIGATORS:

owner of Ackerman & Sons furniture refinishing shop to investigate methylene chloride (MeCl) exposures within the shop. An initial survey was conducted on October 10, 1992, to determine the exposures to furniture stripping solvents (primarily MeCl). An inexpensive ventilation control was then installed in two phases. The first phase included adding exhaust ventilation and enclosing only the furniture stripping booth. A second industrial hygiene survey was conducted on November 20, 1992, to determine the effectiveness of the new ventilation. The wash booth was then enclosed and exhaust ventilation added and a third survey conducted on February 10, 1993. Initial survey results documented personal exposures (averaged over the length of the task) to MeCl ranging from 83 to 523 parts MeCl per million parts of air (ppm). Limited time was spent stripping furniture by individual workers, so 8-hour time-weighted average (TWA) concentrations of MeCl ranged from 2.4 to 177 ppm, which were below the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 500 ppm, but above the proposed OSHA PEL of 25 ppm, and above the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) of 50 ppm. NIOSH considers MeCl a carcinogen and recommends that exposure be limited to the lowest feasible concentration. Exposures to methanol (MeOH) ranged from 39 to 95 ppm, which were all below the 200 ppm NIOSH REL, OSHA PEL, and ACGIH TLV. Once the stripping booth was enclosed and ventilated, airborne concentrations of stripping compounds were greatl