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October 23, 2016

ISO Standard Provides Overview of Frameworks for Developing OELs and OEBs for NOAAs

Lynn L. Bergeson Carla N. Hutton

On November 21, 2016, the International Organization for Standardization (ISO) released ISO/TR 18637:2016, “Nanotechnologies — Overview of available frameworks for the development of occupational exposure limits and bands for nano-objects and their aggregates and agglomerates (NOAAs).”  ISO notes that occupational exposure limits (OEL) are generally substance-specific.  In some case, there is insufficient data to develop an OEL, especially for substances such as nano-objects and their aggregates and agglomerates (NOAA) used in emerging technologies.  Under hazard banding, substances are assigned to a hazard band based on limited toxicity data.  ISO states that to date, few OELs and occupational exposure bands (OEB) have been developed for specific NOAAs and none have been formally regulated by a government agency.  One of the goals of the document is to identify both the similarities and differences in the methods used to develop OELs.  ISO notes that the exposure assessment of nanomaterials, including carbon nanomaterials (such as fullerene, graphene, single-walled carbon nanotubes, and multi-walled carbon nanotubes), metal oxides (titanium dioxide, silicon dioxide, zinc oxide, iron oxide), and metals (silver and gold nanoparticles), remains a challenge in the field of occupational hygiene, as there have been relatively few studies on the characterization of workplace exposures to NOAA.  The primary target audience of the document is occupational safety and health professionals in government, industry, and academia, who have the expertise to develop OELs or OEBs based on the document’s guidance.