EPA is establishing national guidance for minimum data quality requirements to optimize the useability of data collected under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Data useability is the process of assuring or determining that the quality of data generated meets the intended use. The guidance is designed to provide data users with a nationally-consistent basis for making decisions about the minimum quality and quantity of environmental analytical data that are sufficient to support Superfund decisions, regardless of which parties conduct the investigation. EPA workgroups are defining the current uses and associated quality requirements of Superfund data, and developing minimum requirements for each data use category. The fact sheet provides an overview of Guidance for Data Useability in Risk Assessment (EPA/540/G-90/008), highlights key points of the manual, and details where additional guidance is found.