This webinar will provide attendees with an overview of the current understanding of PFAS health effects, including information on individual PFAS with U.S. and international human health toxicity criteria, the adverse health effects used to develop these criteria, and research underway on PFAS exposure and toxicity. A summary of current approaches for assessing risk to PFAS mixtures will be provided.  Various state-of-the practice methods (e.g., new approach methods [NAMs]) for assessing the relative toxicity of PFAS without regulatory toxicity criteria will be presented.  A case study will be used to demonstrate how to apply NAMs for predicting relative toxicity of PFAS without regulatory toxicity criteria and for assessing potential human health risk of PFAS mixtures.