This article provides an overview of what we know and what we still need to know concerning OSH research and practices as it relates to nanomaterials. ‘We’ refers to the OSH community including the NIOSH Nanotechnology Research Center (NTRC) (NIOSH, 2010a,b). Specific examples [e.g. carbon nanotubes (CNT)] of the data needed for risk assessment to support risk management decision-making, focusing on inhalation hazards, are provided. An integrated process is proposed for the evaluation, decision-making, and implementation of OSH research and guidance.