Examples of existing definitions

The document outlines various definitions of nanomaterials used by the ISO, OECD, the European Union, and agencies in the US and Canada. It notes that while many rely on a size range of 1nm to 100nm, specific criteria (such as particle distribution percentages in the EU or property-based definitions in the US and Canada) vary. The author argues that these differing definitions lead to legal uncertainty and inconsistent safety assessments across different jurisdictions and product types.

• The International Organization for Standardization (ISO) defines a nanomaterial as a material with external dimensions, internal structure, or surface structure in the nanoscale, which was modified in 2014 to mean a length ranging from approximately 1nm to 100 nm. This ISO definition serves as the basis for working definitions in the United States, Canada, the United Kingdom, Australia, and the Organization for Economic Co-operation and development (OECD).
• The OECD Working Party on Manufactured Nanomaterials defines a nanomaterial as a chemical that is either a "nano-object" (material confined in one, two, or three dimensions at the nanoscale) or "nano-structured" (having an internal or surface structure at the nano scale), with the nano-scale typically being between 1nm and 100 nm.
• The United States lacks a single regulatory definition for nanomaterials, with different agencies using various working definitions. The Environmental Protection Agency (EPA) uses a definition from the National Nanotechnology Initiative, noting that nanomaterials can have unique properties (optical, mechanical, magnetic, conductive, and sorptive) compared to larger versions of the same chemical. The Food and Drug Administration (FDA) defines them as materials with at least one dimension between approximately 1 nm and 100 nm, or those exhibiting related dimension-dependent phenomena.
• Health Canada defines nanomaterials as those with at least one external dimension, or internal/surface structure, within the nanoscale (1 to 100 nanometers inclusive), or materials outside that size range that still exhibit one or more nanoscale properties or phenomena.
• The European Commission's October 2011 Recommendation defines nanomaterials as natural, incidental, or manufactured materials where 50% or more of the particles in the number size distribution have one or more external dimensions between 1nm and 100nm. This definition includes specific derogations for graphene flakes, fullerenes, and single wall carbon nanotubes with dimensions below 1 nm, and allows for a specific surface area by volume ratio of 60m2/ cm3 to be used as a proxy to establish a material as a nanomaterial.
• The lack of standardized definitions across jurisdictions creates legal uncertainty and inconsistent regulatory approaches. This can result in a substance being regulated as a nanomaterial in one application (such as biocides) but treated as a bulk substance in another (such as cosmetics), or being treated as a nanomaterial in the EU while being viewed as a bulk material in the US.

APA

Center for International Environmental Law (n.d.). Examples of existing definitions. https://www.ciel.org/wp-content/uploads/2015/07/Nano_definition_Nov2014.pdf

Chicago

Center for International Environmental Law. Examples of existing definitions. n.d. https://www.ciel.org/wp-content/uploads/2015/07/Nano_definition_Nov2014.pdf.

Wikipedia

{{cite report |author=Center for International Environmental Law |title=Examples of existing definitions |url=https://www.ciel.org/wp-content/uploads/2015/07/Nano_definition_Nov2014.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{centerforinternationalenvironmentallawndexamples, author = {{Center for International Environmental Law}}, title = {{Examples of existing definitions}}, institution = {Center for International Environmental Law}, url = {https://www.ciel.org/wp-content/uploads/2015/07/Nano_definition_Nov2014.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }