This memorandum, dated May 2013, transmits a separate revised memorandum that provides guidance and a checklist for evaluating the regulatory status of materials that would, under usual circumstances, be commercial chemical products (CCPs). CCPs are not solid waste if they are appropriately stored or managed for use, legitimately reclaimed, or appropriately stored or managed for legitimate reclamation; CCPs are solid waste if they are abandoned by being accumulated, or by being stored, or treated before, or as a means of, being disposed. The checklist is designed to assist in applying this regulatory structure to specific situations and evaluating whether a particular CCP, managed in a particular way, is a solid waste.