Pursuant to the Clean Water Act, the Environmental Protection Agency (EPA) prepares a schedule identifying dispersants, other chemicals, and other spill mitigating devices and substances, if any, that may be used in carrying out the National Contingency Plan (NCP); and the waters and quantities in which they may be used. The EPA proposed to revise Subpart J of the NCP to address the efficacy, toxicity, environmental monitoring of dispersants, other chemical and biological agents, and other spill mitigating substances, as well as public, state, local, and federal officials' concerns on their authorization and use. Specifically, the Agency is considering finalizing revisions to the technical product requirements under Subpart J, including amendments to the effectiveness and toxicity testing protocols, and establishing new effectiveness and toxicity thresholds for listing certain products on the NCP Product Schedule. Additionally, the Agency is considering finalizing amendments to requirements for agent use authorization. The Agency is also considering finalizing revisions to harmonize 40 CFR part 110.4 with the definitions for chemical and biological agents proposed for Subpart J. These changes, if finalized, may help ensure that chemical and biological agents have met rigorous efficacy and toxicity requirements, that product manufacturers provide important use and safety information, and that the planning and response community is equipped with the proper information to authorize and use the products in a judicious and effective manner.