Waterborne Paint Exposure in the Auto Body Collision Repair Industry
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Objectives: The purpose of this study was to characterize workers’ exposures to emerging waterborne coatings used in automotive refinishing systems and observe other work practices associated with using these products. Methods: Ten auto body shops in King County, Washington that use waterborne coatings were recruited to participate in this study. Based on reviews of Material Safety Data Sheets (MSDSs) from commonly used waterborne basecoats, 14 target compounds were selected to characterize exposures to components of these products. Task-based personal air sampling was conducted on 11 painters when applying basecoats. Sampling results were summarized and compared to MSDSs and historical exposure studies of solvent-based paints. Painters’ work practices were also recorded to determine other possible routes of exposure. Work practices recorded included the use of Personal Protective Equipment (PPE), gun-cleaning procedures, waste disposal, and paint booth maintenance. Results: Breathing zone concentrations of aromatic hydrocarbons and polar volatile organic compounds were typically below their respective method limits of quantitation (MLOQ). On average, 11% (SD= 16%) of the aromatic hydrocarbon samples and 23% (SD=19%) of the polar compound samples exceeded their respective MLOQs. All analyte concentrations had threshold limit value (TLV) parametric exceedance fractions below 0.03, and National Institute of Occupational Safety and Health (NIOSH) odor parametric exceedance fractions below 0.05. VOC exposures when spraying waterborne paints were up to 56 times lower than historical studies on VOC exposures to solvent-based paints. Procedures for cleaning paint guns and disposing of waterborne paint wastes varied between shops. Several shops disposed of waste in the municipal solid waste stream without chemical characterization, in violation of state regulations. Painters were observed using lacquer thinner to clean their waterborne paint guns, which is not recommended by manufacturers. Painters were also observed handling waterborne waste with inadequate exposure controls. We observed that the air flow rates in spray booths typically failed to meet OSHA requirements. Conclusions: Workers’ exposures to target compounds when applying waterborne basecoats were typically below their respective MLOQs and regulatory limits. The typical PPE worn by painters should be adequate to protect painters from possible exposures. This study also shows that the waterborne paint exposures during spraying are lower than the historical exposures due to spraying solvent-based paints. However, without maintaining adequate airflow in the paint booths and adequate guidelines for all aspects of handling the paints, workers can still be at risk of exposures to waterborne paints and other chemicals used during non-spraying operations. Therefore, more information is needed on the chemical composition of the waste generated from waterborne paint systems to establish best practices for spray gun cleaning and waste disposal.
- Environmental health