U.S. NIOSH Revises Draft CIB on Health Effects of Occupational Exposure to Silver Nanomaterials

Posted on: September 26, 2018


by Caroline Miller, CIH, CSP

The National Institute for Occupational Safety and Health (NIOSH) has recently published a revision to the draft Current Intelligence Bulletin (CIB) on the Health Effects of Occupational Exposure to Silver Nanomaterials, and announced an online public meeting taking place on October 20, 2018.  The revised draft – which was published in a Federal Register notice on September 18, 2018 – is based on input from comments at a previous public meeting, and replaces the original draft document from January 21, 2016.

What is contained in the revised draft?

In the latest draft CIB, NIOSH proposes a ‘Recommended Exposure Limit (REL) for silver nanomaterials (<100 nanometers primary particle size) of 0.9 micrograms per cubic meter (μg/m3) as an airborne respirable 8-hour time-weighted average (TWA) concentration.’ The REL for silver (metal dust, fume, and soluble compounds) remains 10 μg/m3 as an 8-hour TWA concentration (total mass sample). The current REL for total silver has not been evaluated. The revision is specifically for silver nanomaterials and is “based on preventing workers from developing argyria, which is bluish-gray pigmentation to the skin and mucous membranes, and argyrosis, which is bluish-gray pigmentation to the eyes.”

Silver nanomaterials are used in the manufacture of electronics and textiles and are used as pigments, catalysts, and antimicrobials. In the revised draft CIB, NIOSH suggests that effective risk management practices, like worker exposure assessments, engineering controls, training, and medical surveillance, be applied to processes that produce or use silver nanomaterials to keep worker exposures below the NIOSH REL for either silver nanomaterials or total silver.

Public Feedback

NIOSH is inviting the public to provide feedback on the latest draft CIB.  NIOSH is interested in the public’s opinion of whether the document covers the scientific literature regarding the possible adverse health effects of silver nanomaterials and if the proposed REL and risk management practices are appropriate based on scientific evidence.  Comments on the draft CIB are due November 30, 2018.

Next Steps

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Useful Information

U.S. Department of Health and Human Services (HHS), Centers for Disease Control and Prevention (CDC), NIOSH (2018).  “Revised External Review Draft – Current Intelligence Bulletin: Health Effects of Occupational Exposure to Silver Nanomaterials”:

HHS, CDC, NIOSH. “Revised Draft NIOSH Current Intelligence Bulletin: Health Effects of Occupational Exposure to Silver Nanomaterials.” Federal Register 83 (18 September 2018):


NIOSH, Silver, Nanomaterials, REL, CIB


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