[en] Project Rio Blanco was a joint Government-industry experiment using nuclear explosives to stimulate the flow of natural gas from low permeability formations which could not be economically produced through conventional methods. The project consisted of the simultaneous detonation of three nuclear explosives on May 17, 1973, in a 7,000 foot well in northwestern Colorado. Gas production testing and project evaluation continued through June 1976. The site cleanup and restoration planning phase began in December 1975 and was concluded with the issuance of an operational plan, Project Rio Blanco Site Cleanup and Restoration Plan, NVO-173, in May 1976. Actual site restoration activities were conducted during the period from July to November 1976. The activities throughout the restoration period are summarized and the final site status, including the disposition of all project facilities and the status of all project related wells after plug and abandonment and recompletion work are described