The 2018 U.S. Farm Bill removes hemp and hemp-derived CBD from the Controlled Substances Act

On December 20, 2018, the Agriculture Improvement Act of 2018—widely known as the 2018 Farm Bill (Public Law 115-334)—was signed into federal law after passing the Senate 87–13 and the House 369–47. For the first time since the Controlled Substances Act was passed in 1970, Congress permanently removed a category of the Cannabis sativa L. plant from Schedule I.

How the 2018 Farm Bill defined legal hemp

Under Sections 10113 and 12619 of the Act, Congress drew a legal line based on a single chemical measurement:

• The 0.3% delta-9 THC threshold: The law defined “hemp” as the plant Cannabis sativa L. and any part of that plant—including its seeds and all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers—with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis.
• Removed from the Controlled Substances Act: Hemp meeting that 0.3% delta-9 THC limit was explicitly excluded from the CSA’s definition of “marihuana” and transferred to the regulatory oversight of the U.S. Department of Agriculture (USDA) and state departments of agriculture.

Unintended consequences: CBD and hemp-derived cannabinoids

While lawmakers primarily intended to legalize industrial hemp fiber, grain, and non-intoxicating CBD wellness products, defining legality strictly by 0.3% delta-9 THC by dry weight created a massive national market for hemp-derived cannabinoids—including CBD oils, delta-8 THC converted from hemp CBD, and heavy gummies containing several milligrams of hemp-derived delta-9 THC while staying under 0.3% of the gummy’s total weight. Congress would eventually revisit that definition in November 2025.