The Environmental Protection Agency is finalizing its proposed action to grant a petition submitted by the United States Department of Energy, Richland Operations Office (Energy) to exclude (or `delist') from regulation as listed hazardous waste certain mixed waste (`petitioned waste') following treatment at the 200 Area Effluent Treatment Site (200 Area ETF) on the Hanford Facility, Richland, Washington. This action conditionally grants the exclusion based on an evaluation of waste stream-specific and treatment process information provided by Energy. Wastes meeting the conditions of this exclusion are exempt from the requirements of hazardous waste regulations under the Resource Conservation and Recovery Act (RCRA) of 1976 as amended. In finalizing this action, EPA has concluded that Energy's petitioned waste does not meet any of the criteria under which the wastes were originally listed, and that there is no reasonable basis to believe other factors exist which could cause the waste to be hazardous.