The use of dispersants in response to the Deepwater Horizon incident, both on surface slicks and injected directly into the oil from the well riser, raised many questions about efficacy, toxicity, environmental trade-offs, and monitoring challenges. The Agency is considering amendments to subpart J that would increase the overall scientific soundness of the data collected on mitigation agents, take into consideration not only the efficacy but also the toxicity, long-term environmental impacts, endangered species protection, and human health concerns raised during responses to oil discharges, including the Deepwater Horizon incident. The additional data requirements being considered would aid On-Scene Coordinators (OSCs) and Regional Response Teams (RRTs) when evaluating specific product information and when deciding whether and which products to use to mitigate hazards caused by discharges or threatened discharges of oil. Additionally, the Agency is considering amendments to area planning requirements for dispersant use authorization, toxicity thresholds and advanced monitoring techniques. This action is a major component of the EPA's effort to inform the use of dispersants and other chemical or biological agents when responding to oil discharges, based on lessons learned from the federal government's experiences in responding to off-shore oil discharges, including the Deepwater Horizon incident, in the Gulf of Mexico and anticipation of the expansion of oil exploration and production activities in the Arctic.