The European Commission intends to achieve a common definition for nanomaterials in order to better protect citizens, clearly defining which materials need special treatment in specific legislation. The definition says that nanomaterials are materials whose main constituents have a dimension of between 1 and 100 billionth of a metre and is based, according to the European Environment Commissioner Janez Potočnik, on scientific input and a broad consultation.

European Environment Commissioner Janez Potočnik presented a recommendation that proposes a common definition for the nanomaterials. The recommendation defines a nanomaterial as "a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm – 100 nm." The definition adopted is based on an approach considering the size of the constituent particles of a material, rather than hazard or risk. The aim of this common definition is to get a clear coherent regulatory framework to the industry, and consumers deserve accurate information about these substances.

The definition is based on scientific advice from the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) and the Joint Research Centre (JRC) and it was subject to a public consultation. The definition adopted is also based on an approach considering the size of the constituent particles of a material, rather than hazard or risk. It is foreseen that the definition will help all stakeholders including industry associations, as it brings coherence to the variety of definitions that are currently in use in different sectors.  MEPs at the Environment Committee proposed on the 6 of October to investigate whether the use of tiny particles (nanomaterials) constitute a risk. The definition will be reviewed in 2014 in the light of technical and scientific progress.

Nanomaterials are already being used in hundreds of applications and consumer products ranging from toothpaste to batteries, paints and clothing. Developing these innovative substances is an important driver for European competitiveness, and they have significant potential for progress in areas like medicine, environmental protection and energy efficiency. But as uncertainties remain about the risks they pose, a clear definition is needed to ensure that the appropriate chemical safety rules apply. For example, a European project was presented last June on nanomaterials.