Increasingly, models and tools are used by occupational hygienists, risk assessors and risk managers for estimating exposure to and risk from chemical agents in the workplace. These range from simple, screening tools (tier 1 tools) that provide conservative exposure estimate, to more complex higher tier exposure models. In Europe, tools such as ECETOC TRA, STOFFENMANAGER and ART have been developed and are used predominantly for risk assessment as part of the REACH regulations. Furthermore, tools for estimating exposure to nano-sized particles have been developed (e.g. NANOSAFER, Stoffenmanager-NANO). In recent years, several studies have been carried out to test the performance of these tools.Methods
Several studies were carried out to determine the performance of the exposure tools for chemical agents and nano-materials, including comparison with measurement data as well as inter-user comparisons.Results
The comparison of tool estimates with measurement data suggested that the tier 1 tools appear to be conservative, although this varied between tools and type of exposure. Correlations between the measurement results and tool predictions also varied with tool and exposure type. Furthermore, a wide range of exposure estimates were observed when different users were asked to apply the same tools to the same scenario conditions.Conclusion
Models to estimate exposure and risk are essential elements of the toolbox of occupational hygienists and risk assessors and managers. However, there is increasing evidence that performance varies between tools, type of exposure and scenario conditions. More importantly, users appear to struggle to apply the tools consistently, leading to wide ranges in estimated exposures. There is an urgent need for the development and implementation of generic quality control procedures for use of exposure tools, to reduce the large uncertainties when applying these tools, both to prevent workers from being excessively exposed and unnecessarily implementation of stringent exposure control measures.