In 1974 the United States Department of the Interior announced an oil shale leasing program in the oil shale regions of Colorado and Utah, and by the early 1980s almost all of the major oil companies had established oil shale pilot projects.
In 1974 the United States Department of the Interior announced an oil shale leasing program in the oil shale regions of Colorado and Utah on. By the early 1980s, almost all of the major oil companies had established oil shale pilot projects.