The objective of the BX In Situ Oil Shale 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 one trillion Btus of heat will be injected into a site over a two-year period to heat to retorting temperature a shale zone approximately 550 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. Environmental activities conducted from March 1, 1980 through February 28, 1981 were a continuation of operational monitoring initiated the previous year that included meteorology, water quality and aquatic ecology monitoring.