[Airways and lung disease by metal working fluids]

Metal working fluids (MWF) are used in the manufacturing process to cool and lubricate machined parts. MWF contain the coolant, mostly water-oil emulsions with soluble semi-synthetic or synthetic oils, but also emulsifiers and additives. Reaction products and both bacterial and fungal contamination occur during use. In the present review we listed literature data of dose-effect-relationships with a focus on biological substances. Most studies describe obstructive airways disease due to irritant effects of MWF. Immunoglobulin E mediated airways disease or hypersensitivity pneumonitis have rarely been described. There is no doubt that MWF exert adverse effects on human airways, but there is few data concerning dose-effect relationships. The role of bacterial and fungal contamination or endotoxin exposure cannot be defined by the available information. However, there is some evidence that biological components in MWF may represent the most hazardous substances.