On 18 October 2011 the Commission adopted the Recommendation on the definition of a nanomaterial. According to this Recommendation a "Nanomaterial" means:
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.
In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50 % may be replaced by a threshold between 1 and 50 %.
By derogation from the above, fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials.
The definition will be used primarily to identify materials for which special provisions might apply (e.g. for risk assessment or ingredient labelling). Those special provisions are not part of the definition but of specific legislation in which the definition will be used.
Nanomaterials are not intrinsically hazardous per se but there may be a need to take into account specific considerations in their risk assessment. Therefore one purpose of the definition is to provide clear and unambiguous criteria to identify materials for which such considerations apply. It is only the results of the risk assessment that will determine whether the nanomaterial is hazardous and whether or not further action is justified.
Today there are several pieces of EU legislation, and technical guidance supporting implementation of legislation, with specific references to nanomaterials. To ensure conformity across legislative areas, where often the same materials are used in different contexts, the purpose of the Recommendation is to enable a coherent cross-cutting reference. Therefore another basic purpose is to ensure that a material which is a nanomaterial in one sector will also be treated as such when it is used in another sector.
Detailed and technical information about the definition of a nanomaterial is available in the "questions and answers" section.