Biological monitoring guidance values for chemical incidents.

Biological monitoring is a useful tool to assess occupational and environmental exposure following a wide range of chemical incidents. Guidance values are available from international organisations to help interpret the result of biological monitoring. In addition, guidance values based on the 90th percentile of biological monitoring data obtained under conditions of good exposure control may help identify lapses in control and the need for remedial action to improve controls and reduce risk. In all cases interpretation of biomonitoring results following incidents needs care and in particular reference to the time of sample collection and basis of the guidance values. Biomonitoring guidance values specifically derived for chemical incident scenarios are not available but would be of great help to interpret biological monitoring results.