On October 30, 2018, the National Institute for Occupational Safety and Health (NIOSH) held a webinar on its revised draft document entitled Current Intelligence Bulletin:  Health Effects of Occupational Exposure to Silver Nanomaterials.  The meeting agenda and slide presentation are available in the docket, as well as a list of meeting attendees.  As reported in our September 19, 2018, blog item, the revised draft Current Intelligence Bulletin (CIB) provides an updated scientific literature review of information pertaining to occupational exposure to silver nanomaterials.  The literature review includes studies on the toxicological effects of exposure to silver nanomaterials in experimental animal and cellular systems, the effect of particle size and other properties on the toxicological effects of silver, and NIOSH recommendations on the measurement and control of occupational exposures to silver and silver nanomaterials.  Based on an assessment of these data, NIOSH developed a recommended exposure limit (REL) for silver nanoparticles (<100 nanometers (nm) primary particle size) of 0.9 micrograms per cubic meter (μg/m3) as an airborne respirable eight-hour time-weighted average (TWA) concentration.  The draft REL would apply to processes that produce or use silver nanomaterials.  In addition, NIOSH continues to recommend a REL of 10 μg/m3 for total silver (metal dust, fume, and soluble compounds, as Ag).  NIOSH further recommends the use of workplace exposure assessments, engineering controls, safe work procedures, training and education, and established medical surveillance approaches to prevent potential adverse health effects from exposure to silver nanomaterials.  NIOSH proposes research needs to fill remaining data gaps on the potential adverse health effects of occupational exposure to silver nanomaterials.  The purpose of the public review of the draft CIB is to obtain comments on whether it (1) adequately and clearly describes the scientific literature on the potential adverse health effects of silver nanomaterials, and (2) demonstrates that the NIOSH recommendations on occupational exposure to silver nanomaterials are consistent with current scientific knowledge.  Comments on the draft CIB are due November 30, 2018.