Respiratory health effects of metalworking fluids

Metal machining requires lubrication and dispersion of generated heat. Several distinct classes of metalworking fluids are used to accomplish these goals. Exposure these fluids is widespread in the automotive industry. Our study of acute respiratory effects associated with inhalational exposure to metalworking fluid aerosols in an automotive transmission plant resulted in a number of novel findings: large cross shift decrements in FEV1 and FVC were seen in those with exposure but not in unexposed controls, significant associations of cross shift decrements in FEV1 and FVC were demonstrated with exposure to bacteria; and these associations were much more pronounced in workers with lower baseline (Monday pre-shift) FEV1/FVC ratios. Our identification of the first case series of machinists with biopsy proven hypersensitivity pneumonitis played an important role in establishment of an association of this disease entity with metalworking fluids.