In the fifteen years since the fission process began generating highly radioactive isotopes in large quantities, many methods have been utilized for radioactive waste disposal. In this same interval greater quantities of radioactive wastes have been generated and disposed to the environment or stored in interim containers at Hanford than at any other atomic installation. This experience will be discussed with the objectives of pointing out the present state of our knowledge and practice, and of indicating probable future trends. The problems encountered in handling, storing, and diluting radioactive liquid wastes are similar in many respects to those encountered in other chemical industries. Radioactive waste is, however, unlike other industrial wastes in that physical and chemical processing are of no avail in destroying the toxic property of the waste. It can be transferred from one physical or chemical carrier to another, diluted, and concentrated; but the only process for eliminating the radioactivity is the built-in radioactive decay process itself. It is for this reason that some disposal methods are better referred to as interim storage methods. Radioactive wastes are furthermore unique in that only extremely small concentrations of isotopes may be permitted entry to the body. For example, whereas nonradioactive arsenic can be tolerated to the extent of 0.05 μg per ml in drinking water (1),² the maximum permissible concentration (MPC) of radioactive arsenic-76 is 3 × 10⁻⁹ μg per ml (2). The national interest in disposal of radioactive wastes was highlighted in the Public Hearings on Industrial Radioactive Waste Disposal last January before the special Sub-Committee on Radiation of the Joint Committee on Atomic Energy (3). During these hearings the subject of radioactive waste disposal was reviewed by many representatives from various atomic installations, and by consultants in geology and hydrology. It is generally agreed that safe, economical ways will be found to dispose of all nuclear wastes in the forthcoming era of nuclear power development; however, much research is required. The practices used to date have been helpful guides to future disposal, particularly in regard to low-level wastes.