CASE-STUDY - CONTROL OF METHYLENE-CHLORIDE EXPOSURES DURING FURNITURESTRIPPING

Methylene chloride a potentia I occupational carcinogen, is one of the principal solvents used for furniture stripping. Methylene chloride e xposures among workers in furniture stripping operations have been fou nd to be high. This article describes a furniture stripping operation at a sheltered workshop before and after the ventilation system was mo dified. Previous to ventilation system modifications, workers who were stripping fu rn itu re had exposures to methylene chloride ranging fr om 600 to 1150 ppm. These high exposures and an evaluation of the vent ilation system prompted the design and installation of a modified vent ilation system. Primary modifications included installing a local vent ilation hood, decreasing the velocity of makeup air entering the strip ping area, removing a contaminated charcoal adsorption bed, and improv ing work practices. The modified system was arranged into three config urations that included a slot hood, a downdraft hood, and a combinatio n slot and downdraft hood. The three configurations were evaluated ove r a three-day period, and it was found that they controlled the worker 's personal exposures to methylene chloride while stripping to 28 ppm for the combination configuration, 30 ppm for the downdraft configurat ion, and 34 ppm for the slot configuration. Although the exposures are above the proposed Occupational Safety and Health Administration perm issible exposure level of 25 ppm,these results show a substantial impr ovement over the existing ventilation system. The ventilation system d escribed is applicable to other furniture stripping facilities if rins e area local ventilation is improved.