Many regulatory bodies around the world have separately developed definitions of “nanomaterial” to identify materials of potential interest, resulting in inconsistent definitions among regulatory organizations. Such inconsistency complicates the regulatory process by impeding the ability of governments to share comparable information and increases compliance costs for industry.

On March 13, 2013, the Nanotechnology Panel presented a poster titled Comparative assessment of nanomaterial definitions and considerations for implementation at the 52nd Annual Meeting of the Society of Toxicology. The panel conducted a comparative assessment of regulatory definitions of nanomaterials and identified inconsistencies that may impede communication and increase regulatory compliance costs.

In the poster, the Panel suggests consideration of the following material properties in any evaluation of nanomaterials:

  • Solid, particulate substances;
  • Intentionally manufactured at the nanoscale;
  • Consisting of “nano-objects” as defined by the International Organization for Standardization (ISO) but without the word “approximately” to describe the size range;
  • A weight-based cutoff for ISO-defined nanomaterial content;
  • Consideration of aggregates and agglomerates of nanomaterials; and,
  • Exclusion of aggregates and agglomerates if they cannot be readily broken down into nano-objects.

These elements can be used as a first step to identify “nanomaterials” that may be of regulatory interest. These recommendations are designed to reduce ambiguity and confusion so stakeholders can have a clear understanding of how to comply with regulation.

Further evaluation of materials identified by this definition will involve consideration of hazard, use patterns, and potential human and environmental exposures on a case-by-case basis.


Review: Release of Nanomaterials From Solid Nanocomposites

Workshop Report Available: Regulatory Toxicology and Pharmacology, Vol 68, no. 3.


Workshop Report: Occupational Exposure Limits for Engineered Nanomaterials

Workshop Report Available: Particle and Fibre Toxicology 2014, 11:17.

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