Characterization and Evolution of Exposure to Volatile Organic Compounds in the Spanish Shoemaking Industry over a 5-Year Period

This study measured inhalation exposure to 13 volatile organic compounds (VOCs) among workers in the leatherwear industry in Spain, examined the changes in those exposures over a 5-year period, and documented local exhaust ventilation practices that affected exposure. In collaboration with an occupational risk prevention company, air samples were collected from 849 workers' personal breathing zones using personal air pumps with activated charcoal tubes. VOCs were analyzed using a GC/MS-optimized method modified in our laboratory from that proposed by Spanish authorities (INSHT). Airborne concentrations were compared with occupational exposure limit (OEL) values from the European authorities. The most frequently detected VOCs were acetone (98.1%), toluene (94.8%), n-hexane (71.2%) and other C6-C7 branched alkyl hydrocarbons (97.5%). Other frequently detected VOCs were MEK (64.9%), ethylacetate (60.7%), and cyclohexane (29.3%). Benzene was detected in 24.6% of samples. Although all the samples were taken while workers performed tasks judged to have the highest VOC exposure potential, only 14% of samples showed excessive aggregate exposure, and chemical-specific OELs were exceeded in a relatively small number of cases: 7.2% for n-hexane, 2.8%,for toluene, 0.6% for acetone, and 0.4% for hexane isomers. Over the study period, a diminished use of n-hexane in solvent formulations and an increased use of branched hexane and heptane isomers were observed. Six factors relating to work location conditions and types were evaluated. Most high-exposure cases were associated with three task types. The presence of local exhaust ventilation was an important exposure control, but significant exposures despite the use of local exhaust were observed. Although n-hexane exposures significantly decreased over the study period, the overall level of VOC exposure did not decrease. More effective exposure prevention measures need to be implemented.