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The objectives of this study were both to evaluate the level and correlations of hazardous agents and to suggest measures to control industrial hygiene problems caused by using water-soluble metalworking fluids(MWF). Geometric mean of formaldehyde(0.039 ppm) was higher than criteria of NIOSH(0.016 ppm). Fomaldehyde, originally existed in the biocide, is released and used to kill microbes in soluble MWF. Microbe concentrations were above 10⁴ No./mL in 14 MWF tanks among 20 tanks surveyed. Nitrosamines that is formed by reaction of nitrosating group and amines was detected to 18.4-47.1 ㎍/㎥. Formaldehyde concentration was low when microbes were abundant(r=0.67, p=0.011), and high when open tank area was wide(r=0.75, p=0.012). The significant relationship between pH and microbes(r=-0.76, p=0.003) was also observed. The predominant bacteria species in MWF were Pseudomonas spp., Bacillus spp., Comamonas testosteroni, Acinetobacterhaemolyticus, Bordetella bronchiseptica in order. Therefore, hazardous agents emitted by using water-soluble MWF seems to be correlated microbial growth. In order to minimize worker´s exposure to several hazardous agents by an water-soluble MWF and to increase productivity, microbial growth must be controlled to the lowest level as possible. Administrative control as well as engineering control must comprehensively be applied to control microbe´s growth in water-soluble MWF.
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