The findings of this report are based totally upon the information which was submitted in good faith by the various Federal offices. The Environmental Protection Agency made no attempt to verify or corroborate the information submitted. The hazardous substances reported fell into three categories: chemical and biological warfare agents, radioactive materials, and conventional explosive weapons and the chemicals involved in preparing them. The Federal installations reporting ultra-hazardous substances presented in this report are the following: Rocky Mountain Arsenal; AEC Rocky Flats Plant; Pueblo Army Depot; Fort Carson; AEC Grand Junction Compound; and Buckley Air National Guard Base. A complete assessment of the risks involved to the general population must await a further evaluation of current procedures for storing, handling, using and ultimately disposing of these substances. The degree of risk can best be formulated in terms of a 'maximum probable occurrence,' since leakage, explosions, fires, or other disasters involving these substances would most likely affect only a portion of the total amount of the substance listed, and under abnormal circumstances that do not occur with much frequency. The question that has to be answered through some open public decision-making process, is whether that risk is worth taking, particularly when these substances are located in densely populated urban areas.