The history of the oil shale industry started in ancient times. The modern industrial use of oil shale for oil extraction dates to the mid-19th century and started growing just before World War I because of the mass production of automobiles and trucks and the supposed shortage of gasoline for transportation needs. Between the World Wars oil shale projects were begun in several countries.[2]
After World War II, the oil shale industry declined due to increased accessibility to conventional crude oil.[a] As of 2010, oil shale was commercially used in Estonia, China and Brazil, while several countries are considering to start or restart commercial use of oil shale.[2]
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