Background The development of nanomaterials - defined as having at least one dimension of 100 nanometres or less – is a particularly exciting area of science and industry. Nanomaterials and nanotechnologies are expected to yield numerous technological advances, including in health care through new treatments and methods of drug delivery. More than 300 European businesses are now involved in the production of substances at nanoscale and production and sales are soon expected to reach 10 million tonnes and more than EUR 450 billion respectively. The EU Regulation REACH requires manufacturers and importers to demonstrate that they have appropriately identified and assessed all the associated risks of any chemical substance manufactured or imported in quantities of one tonne or more per year per company. A relevant registration dossier must be submitted to the European Chemicals Agency (ECHA), including all information on physicochemical, toxicological and ecotoxicological properties, and the corresponding risk assessment based on a chemical safety assessment (CSA). The unique properties of nanomaterials that create opportunities for exciting new uses also create possibilities of unwanted health and environmental risks, for example excessive absorption of nanoparticles through the skin. Furthermore, there is a lack of information on toxicological and ecotoxicological properties, dosimetry parameters or even standardised risk assessment methods for nanomaterials. Objectives The 'REACHnano' project aims to provide the industry and stakeholders with easy-to-use tools to support the risk assessment of nanomaterials along their lifecycle. It thus seeks to support the implementation of the REACH regulation with regard to nanomaterials and ultimately improve the protection of the environment and human health from risk. The project seeks to consolidate the knowledge base on nanomaterials-related risk and risk assessment. It will collect and evaluate the adequacy of the available information on the physicochemical, toxicological and ecotoxicological properties of nanomaterials and related exposure-, use- and risk-management measures. 'REACHnano' plans to develop a complete selection of standard testing models to be used in the risk characterisation process for nanomaterials and a complete description of the current exposure scenarios across the nanomaterials lifecycle. These will cover the existing operating conditions, efficient risk management measures and estimated exposure levels. The complete set of innovative tools supporting the risk assessment process, information exchange and the information search process will be made freely available in the form of a web-based toolkit and disseminated widely to stakeholders, including SMEs and competent authorities. Webinars, workshops and training will support use of the tools and thus implementation of the REACH regulation on nanomaterials. Expected results The main outcome of the project will be a web-based toolkit, available for free to all European stakeholders, delivering: Improved risk assessment of nanomaterials along their lifecycle, including standard testing models and exposure scenarios; Improved implementation of the REACH regulation; Decreased pollution risk to the environment and human health from new and developing nanotechnologies; and A reduction by 5-10% of nanoparticles escaping to the air, water and/or soil from the production process, depending on the specific measures implemented in each exposure scenario.