Characterizing full-shift worker exposures to VOCs in small-sized auto repair shops in the Tucson, Arizona, USA metropolitan area

Auto repair shops employ 1% of the US labor force. These workers are constantly exposed to volatile organic compounds (VOCs), which have known and often irreversible health effects, yet exposure studies are sparse. Our goal was to assess what exposure factors were related to total personal and shop-level specific VOC exposures for entire shifts in marginalized, predominantly Spanish-speaking workers in auto repair shops. Full-shift, real-time worker exposure factors like activities and ventilation conditions were recorded, along with personal total VOCs and shop-level specific VOC samples. The relationship of total VOCs with activity and ventilation, along with shift and shop, was analyzed using linear mixed effects modeling. Specific VOC concentrations were combined into hazard scores for potential health risks based on EPA inhalation reference or reference dose. Personal exposures were characterized by episodic peaks, with the highest peaks during spraying brake cleaner and painting activities in 22/35 shifts. Shift within shop and shop accounted for about half the variation in total VOC exposures to workers (35% and 15%, respectively), while activity and ventilation explained almost none. Acetone and toluene were detected in all samples. While worker exposure patterns were characterized by infrequent but very high peak exposures to total VOCs related to aerosolization activities, activities were only slightly predictive of VOC exposure overall. Instead, shift within shop and shop explained just half the variability. While additional study on exposure factors is needed, this should be done with a focus on interventions tailored to worker and shop.