In an ideal world, regulation should seek to facilitate and harmonize the identification, characterization and control of all hazards, exposures and risks associated with substances and products, to protect human health and the environment, while at the same time enhancing industrial competitiveness and innovation. To date, this is the center of current global debates on nanotechnology and its products. A challenging situation now occurs. Nanotoxicology data are required, many studies are ongoing and yet the questions remain open as to whether the obtained data are appropriate and what existing data can be used here. A critical aspect, perhaps even the most critical aspect of nanotoxicology, is the availability of no-effect data. We propose here a framework that includes all scientific data on nanomaterials which will contribute to the development of harmonized guidelines for nanomaterial safety studies. (C) 2011 Elsevier Ltd. All rights reserved.