Biological monitoring to assess exposure from use of isocyanates in motor vehicle repair

Objectives-To develop a method for the measurement of a maetabolite of hexamethylene diisocyanate (HDI), an isocyanate, and use it to assess the exposure of sprayers employed in motor vehicle repair shops. Methods-Urine samples were taken from sprayers wearing personal protective equipment and spraying in booths or with local exhaust ventilation, from bystanders, and from unexposed subjects. Samples were analysed for a metabolite of HDI, hexamethylene diamine (HDA), by gas chromatogaphy-mass spectrometry (GC-MS). Results-HDA was detected in four sprayers and one bystander out of 22 workers. No NDA was detected in the urine of unexposed subjects. Conclusions-Exposure to isocyanates still occurs despite the use of personal protective equipment and the use of a booth or extracted space. Health surveillance is likely to be required to provide feedback an the adequacy of controls even if such precautions are used and to identify eases of early asthma. Biological monitoring can provide a useful additional tool to assess exposure and the adequacy of controls in this group of exposed workers.