The National Nanotechnology Initiative (NNI) held a webinar on November 16, 2021, entitled “What We Know about NanoEHS: Risk Assessment and Risk Management.” The webinar’s speakers explored the impact of advances in risk assessment and risk management on the safe and responsible development of nanotechnology. The panel included:

• Rick Canady, Director and Founder, NeutralScience L3C;

• Igor Linkov, Research Physical Scientist, Environmental Laboratory, U.S. Army Engineer Research and Development Center (ERDC);

• Mary Schubauer-Berigan, Deputy Director, Evidence Synthesis and Classification Branch, International Agency for Research on Cancer (IARC), World Health Organization (WHO); and

• Paul Schulte, Director, Division of Science Integration, National Institute for Occupational Safety and Health (NIOSH).

Schulte introduced the panel and provided the basis for discussing developments in the environmental, health, and safety aspects of nanomaterials (nanoEHS) historically, what researchers have learned, and where research is headed. Schulte noted that the innovation of nanoparticles has led researchers to conduct risk assessments and evaluate risk management in groups or categories, rather than by individual particles. Schulte highlighted the work that has been done in occupational safety and exposure studies, but stated that most of this research has been limited to extrapolating animal studies to humans to develop occupational exposure limits. Schulte stated that epidemiological studies in humans could help ensure that data on classification groups properly address particle overload and the effects of exposure to various combinations of nanoparticles in risk management policy.

Schubauer-Berigan focused her presentation on the work that has been done in the past ten years on multi-walled and single-walled carbon nanotubes and carbon nanofibers. Schubauer-Berigan discussed studies that show biomarkers that may be able to help in exposure assessment and hazard identification. She discussed the variance in respiratory and dermal exposure in occupational workers, but noted that no one aspect of exposure was most relevant at this time. Future studies in occupational exposure settings will work to address these questions. Schubauer-Berigan did note that multi-walled carbon nanotubes have been listed for re-evaluation by IARC and that this was of particular concern for bulk materials. Future research will need to address risk assessments and evaluations involving bulk materials blended with multi-walled and single-walled carbon nanotubes and carbon nanofibers.

Canady shifted the discussion to the real-life applicability and everyday use of the research that has been produced. Canady spoke to how nanoEHS managers and regulatory bodies can move forward with this information to promote and protect worker safety. He noted that much of the data on exposure assessments is challenging to apply as the studies vary in particles, doses, concentrations, and potency values. He expressed concern that nanoparticle toxicity research can be too varied to assess threshold-based hazards. Canady’s proposed solution is to develop regulatory decision matrices and fund further research so as not to stifle agencies or industry innovation.

The final panelist of the day, Linkov, expanded on Canady’s proposition, likening research developments in nanotechnology to developments in the knowledge of COVID-19. Linkov asserted that past knowledge and lessons in conventional chemical risk assessment and management can be used to build off emerging research in the nanoEHS field. He expressed concern that exposure and toxicity assessments may not adequately represent particle migration. Linkov advocated for a regulatory approach that is similar to the regulatory approach of conventional chemicals. Linkov noted that no matter how good risk assessments become, there will always be a gap between the risk assessment and the regulatory field because innovation will accelerate faster than the ability to acquire data. His solution to this gap is to use the known data and historical risk management techniques and apply them to new materials.

Heidi M. Guenther contributed to this article.