EPA's Region 4 requested that the Science Advisory Board provide advice on the U.S. Navy's assessment of potential human health and environmental risks from Polychlorinated Biphenyl (PCB) risks associated with the planned deployment of the ex-Oriskany, a World War II era aircraft carrier, as an artificial reef in the Gulf of Mexico. Regional 4 asked for assistance because the U.S. Navy applied for a necessary risk-based PCB disposal approval in accordance with the Toxic Substances Control Act (TSCA) and implementation of Federal PCB regulations (40 CFR Part 761) prior to sinking the vessel with non-liquid PCBs onboard. The EPA may approve such an application if it finds the disposal action will not pose an unreasonable risk of injury to human health or the environment. To evaluate the potential transfer of non-liquid PCBs to the marine environment and the subsequent risk that they might pose to human and ecological receptors using the artificial reef, the Navy performed leaching studies of different on-board PCB containing materials followed by fate and transport modeling of the leaching results to evaluate how released chemicals might behave in the near-reef marine environment. The U.S. Navy also developed a fate and transport model known as the Prospective Risk Assessment Model (PRAM). EPA's Region 4 asked the SAB to provide advice on the leaching studies, the PRAM, and the characterization of potential risks.