History of the oil shale industry in the United States

The history of the oil shale industry in the United States goes back to the 1850s; it dates back farther as a major enterprise than the petroleum industry. Although the United States contains the world's largest known resource of oil shale, the US has not been a significant producer of shale oil since 1861.

Source: Wikipedia — History of the oil shale industry in the United States (CC BY-SA 4.0)