The objective of this project is to demonstrate the technical feasibility of using superheated steam as a heat carrying medium to retort in situ the oil shale in the Green River Formation "leached zone" and provide a mechanism for the recovery of this shale oil with a minimum impact on the environment. Utilizing primarily the natural porosity in the "leached zone," approximately 450 billion BTU of heat have been injected into a site over a 2 year period to heat to retorting temperature a shale zone approximately 540 feet thick and covering about one acre. The field project is located at Equity's BX in situ site in Rio Blanco County in Northwestern Colorado.