Substantial advances in human health and ecological risk assessment have been achieved by the risk assessment community; however, challenges remain, such as providing credible scientific information on a timely, efficient basis to support decisions for industrial chemicals and pesticides. Current risk assessment data generation requirements-including animal welfare concerns and the volume, appropriateness, and cost of required data-and the large number of chemicals requiring evaluation are a challenge confronting the chemical industry, national and international regulatory agencies, and associated stakeholders (Bradbury et al. 2004). The lack of hazard data for many chemicals and the need to improve the efficiency and quality of risk assessment and management of chemicals are driving forces behind implementation of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Food Quality Protection Act (FQPA), and European Union (EU) legislation being implemented under the auspices of the registration, evaluation, authorization, and restriction of chemicals (REACH) framework (http://ec.europa.eu/environment/chemicals/reach.htm).