EPA Region X, the Puget Sound Water Quality Authority (Authority) and the Washington Department of Ecology (Ecology), requested November 1988 that the National Enforcement Investigations Center (NEIC) rank Puget Sound are federal facilities according to their relative potential for having environmental problems. These facilities were ranked using a modified version of NEIC's Multi-Media Priority Ranking Model which has been successfully used to rank federal facilities in the various EPA Regions. Facilities are ranked using environmental rating criteria based on the type and magnitude of activities in the various media which actually or potentially could cause environmental contamination [Table 1]. These activities include past and present hazardous waste generation and management, wastewater discharges, air emissions, and hazardous and toxic materials handling and storage. To rate the Puget Sound facilities, additional environmental criteria related to the Puget Sound Water Quality Management Plan were established. These criteria address stormwater/nonpoint runoff, sediment contamination, natural resources/wetlands/shellfish, industrial pretreatment, spills, pesticides use, and compliance with environmental statutes and regulations.