Guidance on California Proposition 65 and Hemp Products

Guidance on California Proposition 65 and Hemp Products

Revised April 2020

Published: Wednesday, April 15, 2020

This document was revised in April 2020 to address:

  • The addition of tetrahydrocannabinol (THC) to the list of Prop 65 chemicals as a reproductive toxin on January 3, 2020
  • Marketers have until January 3, 2021 (one year grace period) to provide warnings for their products if required
  • A safe harbor has not been determined for THC, so any detectable amount of THC in a hemp product may require a warning to be provided
  • The THC listing does not specify routes of exposure, so warnings may be needed for products taken orally, applied topically, or inhaled
  • The potential application of the “naturally occurring” provision to hemp products


Consumer goods sold in the State of California are, with certain exceptions, subject to that State’s Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986. The regulations that have been implemented in the years since the Proposition was passed place specific warning requirements on marketers of products sold in the State of California if the product contains chemicals listed by the State as carcinogens or reproductive toxicants. Failure to provide such warnings can result in action by the California Attorney General or by “any person in the public interest.”

Proposition 65 requires persons doing business to provide “clear and reasonable” warnings prior to exposing individuals to chemicals known to the State to cause cancer and/or reproductive toxicity. The State is required to publish a list of the chemicals it considers to cause cancer and/or reproductive toxicity.

In the past decades, numerous companies that sell or manufacture herbal products, including brand marketers, contract manufacturers, and retailers, have been the subject of complaints filed or threatened by several organizations and individuals and local district attorneys and the state attorney general. These lawsuits have alleged that the products sold by these companies contain amounts of heavy metals (primarily lead, and in some cases arsenic, cadmium and mercury) and other listed chemicals that require a warning. Companies that had not provided a warning prior to receipt of complaints have reached settlements that have resulted in payments of up to $682,000 per company, with average settlements in the range of $85,000 to $100,000 per company.

Also of concern, are other chemicals on the Proposition 65 list that may be used in the cultivation and processing of hemp and marijuana, such as the pesticides myclobutanil and carbaryl, for which some cannabis businesses have received Proposition 65 notices.

In January 2020, Δ9-tetrahydrocannabinol (Δ9 THC) was added to the Proposition 65 list as a chemical known to cause reproductive toxicity. The scientific basis for this classification is available from OEHHA. While Δ9 THC is present at only trace levels in hemp products, companies marketing hemp products in California should evaluate whether a warning is needed for these products.

This document was prepared with a narrow focus; it is concerned only with the regulatory and liability implications of Proposition 65 for hemp and hemp-derived products, including cannabidiol (CBD), sold in the State of California. This document does not address the implications of Proposition 65 for marijuana products. It is not intended to address any other elements of Proposition 65 except as necessary for the present purpose, nor does it serve as a substitute for this law, its implementing regulations, or legal counsel.

AHPA has also produced the document Guidance on California Proposition 65 and Herbal Products, which addresses the impact of this regulation to the broader herbal products industry and may also be of interest to the hemp industry. Another AHPA document, Guidance on California Proposition 65 and Cannabis Products, addresses the specific impact of this law on the cannabis (non-hemp) products industry. AHPA produces periodic webinars on Proposition 65 to keep members of the regulated industry up to date on the latest developments from OEHHA regarding lead and other Proposition 65 listed chemicals. For more information, visit AHPA's Prop 65 webpage.


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