EPA's Risk-Screening Environmental Indicators (RSEI) is a geographically-based, multimedia model and prioritization tool that helps policy makers, researchers, and communities quickly analyze large amounts of data on Toxics Release Inventory (TRI) listed toxic chemicals. RSEI incorporates information from EPA’s TRI database, which tracks certain toxic chemical releases and waste management activities at federal facilities and larger industrial facilities across the United States and its territories. RSEI incorporates over 30 years of TRI data, three U.S. censuses, toxicity and physicochemical properties for more than 400 toxic chemicals, and geographical information for more than 50,000 facilities and thousands of streams and other water bodies. All of this information is used to model and map the environmental fate and transport of each toxic chemical through the environment and the potential impacts that may result. The RSEI model calculates numeric results that are designed to be compared to other RSEI model generated results. These RSEI results are designed to help users contextualize, understand, and better communicate the relative hazards and potential for risks posed by certain waste management activities of TRI chemicals (e.g., from releases to the environment). RSEI results and custom analyses can be used for screening-level activities such as trend analyses that compare potential risk-related impacts from year to year, or for ranking and prioritizing toxic chemicals, facilities, industry sectors, or geographic regions for strategic planning. RSEI can also be used in conjunction with other data sources and environmental information, to help policy makers, researchers, and communities establish priorities for further investigation and to look at changes in potential health impacts over time.