The past decade has witnessed an extraordinary increase in research progress and innovation on ultrathin two-dimensional (2-D) nanomaterials. These 2-D nanomaterials include industrial scale materials, such as graphene, as well as emerging materials such as hexagonal boron nitride, silicene, molybdenum disulfide, and many others that have generated considerable interest as they demonstrate a vast array of unique physical properties. Two-dimensional nanomaterials offer great potential in numerous applications such as in electronics, energy storage, water remediation, paints and coatings, sensors, lighting, composites, and biomedicine. As the utilization of 2-D nanomaterials continues to rise, with greater expansion into industrial applications, the potential for workplace and environmental exposures throughout the life cycle of these materials will successively increase as well. To date, there have been relatively few studies found in the published literature evaluating the toxicity of these materials, and even fewer data are available regarding workplace exposures and the development of exposure assessment methodologies. In FY20 NIOSH identified an additional 21 companies potentially handling graphene or other 2-D nanomaterials. The company database for this project now consists of 88 US based 2-D nanomaterial companies. NIOSH has contacted an additional 31 companies by email and a phone call to discuss participation in this study. Five companies have agreed to participate in the study. Three companies (of the five) had a scheduled date to complete the industrial hygiene site assessment prior to the COVID-19 travel restrictions being put in place. NIOSH has remained in contact with these companies and they are still interested in participating once travel restrictions are lifted. An additional four companies have expressed initial interest in participating in the study. In FY20, NIOSH completed one industrial hygiene site assessment at a secondary manufacturer, enrolled study participants and collected air samples for evaluation of inhalable elemental carbon, respirable elemental carbon, and transmission electron microscopy. NIOSH has obtained 4 different types of graphene materials of commercial relevance and varying surface areas to determine aerosol characteristics (dustiness and mass median aerodynamic diameter). The experimental design and standard operating procedures to conduct the aerosol characterization experiments on the various graphene materials is being developed and those studies will begin in FY21.
