Kentucky was the greatest producer of hemp in the United States during the 19th and 20th centuries, when it was the source of three fourths of U.S. hemp fiber. Production started to decline after World War I due to the rise of tobacco as the cash crop in Kentucky and the foreign competition of hemp fibers and finished products. In 1970, federal policies virtually banned the production of industrial hemp during the war on drugs saying all Cannabis sativa is a Schedule I controlled substance. Federal law under the Agricultural Act of 2014 allowed research back into hemp. Kentucky began production again with 33 acres in 2014. As of the 2016 harvest season, only two U.S. states other than Kentucky had over 100 acres (40 ha) in hemp production: Colorado and Tennessee. The first 500-acre commercial crop was planted in Harrison County in 2017, and research permits were issued for over 12,000 acres (4,900 ha) that year. The 2016 documentary Harvesting Liberty concerns the 21st century Kentucky hemp industry.