Today's action finalizes the retention of the mixture rule and the derived-from rule in the Resource Conservation and Recovery Act (RCRA), with two revisions. The mixture and derived-from rules ensure that hazardous wastes that are mixed with other wastes or that result from the treatment, storage or disposal of hazardous wastes do not escape regulation and thereby cause harm to human health and the environment. EPA is finalizing two revisions to the mixture and derived-from rules. These revisions would narrow the scope of the mixture and derived-from rules, tailoring the rules to more specifically match the risks posed by particular wastes. The first revision is an expanded exclusion for mixtures and/or derivatives of wastes listed solely for the ignitability, corrosivity, and/or reactivity characteristics. The second revision is a new conditional exemption from the mixture and derived-from rules for "mixed wastes" (that is, wastes that are both hazardous and radioactive).