[en] Development of environmental protection requirements for radioactive wastes basically involves: (1) features of radioactive materials that require them to be designated as radioactive wastes and their hazard potential over time and at various levels of controls, (2) the importance of risk estimates in arriving at levels of control and the factors that should be reflected in such determinations, (3) the goals of control and the types of institutional, engineered, and natural-barrier controls for meeting such goals, (4) the approaches for determining the allowable levels of short- and long-term risks associated with various means of disposal for types of waste materials, and (5) other considerations for environmental protection such as retrievability, monitoring, and transfer of information to succeeding generations. This background report addresses these five areas in sequence in order to make recommendations for environmental protection criteria which are to be used in the development of environmental standards for major classes of radioactive waste