Risk assessment approaches and research needs for nanomaterials: An examination of data and information from current studies

Risk assessment is an important component in the development of effective risk management strategies. Toxicology, epidemiology, and workplace exposure data are very limited for new engineered nanomaterials, although the number of toxicology studies in this area is growing rapidly. Data are available from existing human and animal studies of exposure to airborne ultrafine and fine particles and fibers, and these can be used as "benchmark" materials for comparison to new nanomaterials. In this paper, we examine several risk assessment and risk management options to evaluate and control exposures to reduce the risk of adverse health effects in workers producing or using nanomaterials. These options include quantitative risk assessment (QRA) using available dose-response data from chronic or subchronic inhalation studies in rodents; comparative potency analysis based on toxicological studies of ultrafine or fine particles; evaluation and adjustment of current exposure limits for similar materials; and hazard assessment and control approaches. As more data become available on new nanomaterials, more precise estimates using QRA can be developed. In the meantime, the existing scientific literature on particles and fibers can be used to develop preliminary hazard or risk estimates for nanomaterials and provide a basis for effective risk management approaches.