EPA outlined plans to initiate the rulemaking process for two new actions under the hazardous waste law, reflecting the agency's focus on using best available science and leveraging authorities to combat this shared challenge. EPA is announcing the initiation of two rulemakings. First, the agency will initiate the process to propose adding four PFAS chemicals as RCRA Hazardous Constituents under Appendix VIII, by evaluating the existing data for these chemicals and establishing a record to support such a proposed rule. The four PFAS chemicals EPA will evaluate are: PFOA, PFOS, PFBS, and GenX. Adding these chemicals as RCRA Hazardous Constituents would ensure they are subject to corrective action requirements and would be a necessary building block for future work to regulate PFAS as a listed hazardous waste. The second rulemaking effort will clarify in our regulations that the RCRA Corrective Action Program has the authority to require investigation and cleanup for wastes that meet the statutory definition of hazardous waste, as defined under RCRA section 1004(5). This modification would clarify that emerging contaminants such as PFAS can be cleaned up through the RCRA corrective action process. These actions build on EPA's broader strategy to comprehensively address PFAS pollution across the country.