Hemp is currently a Schedule I federally controlled substance, in the same legal category as LSD, heroin, and Ecstasy. Like all forms of cannabis, it was criminalized in 1970, partially because Congress was worried that law enforcement couldn’t tell the difference between hemp and marijuana. “There was tremendous biological understanding of the difference, but Congress was not making policy based on this—they were basing it on fear,” said John Hudak, a senior fellow at the Brookings Institution and the author of Marijuana: A Short History.Now, four years after universities and state agriculture departments were allowed to begin growing limited quantities of hemp for research purposes, Congress is expected in September to make the crop legal for Americans to grow for the first time in nearly 50 years. Legalization as part of the 2018 omnibus farm bill would be a major victory for American hemp producers, who believe hemp cultivation could become a billion dollar–plus industry, given hemp’s growing use in pharmaceuticals, food, and textiles.