Engineered nanomaterials present new challenges to understanding, predicting and managing health risks to workers. As nanotechnology applications and uses expand, safety of these emerging materials is identified as one of the research priorities. It has been shown that the physical characteristics of nanoparticles can influence their effects in biological systems, but results from available studies are insufficient to elucidate the potential health concerns. Research efforts have to address knowledge gaps in potential toxicity of nanomaterials, occupational exposure measurement and effective risk management procedures. In this area, European level collaboration is an obvious choice due to the complexity of the issues.