Until recently, though, federal law made little distinction, considering hemp and marijuana identically. Both were essentially made illegal in 1937 with the Marijuana Tax Act, and after the passage of the Controlled Substances Act of 1970, cannabis was listed in the most restrictive controlled substance category by the U.S. Drug Enforcement Administration: schedule I, which also includes substances such as LSD and heroin. But federal restrictions on what is now called “industrial hemp,” cannabis with extremely low levels of THC, began to loosen with the passage of the 2014 Farm Bill, according to Jim Drews, turfgrass and seed program manager with the Maryland Department of Agriculture.