- On January 3, 2021, California’s cannabis (marijuana) smoke and delta-9 THC Proposition 65 reproductive toxicant listings take effect.
- Cannabis products currently sold without warnings may need warnings.
- Cannabis products sold with warnings may need updated warnings.
California’s Office of Environmental Health Hazard Assessment (OEHHA) added “cannabis (marijuana) smoke” and “Δ9-tetrahydrocannabinol (Δ9-THC)” as reproductive toxicants to its list of “Chemicals Known to the State to Cause Cancer or Reproductive Toxicity” on January 3, 2020.
Businesses that manufacture and sell products in California have 12 months from the date of a new chemical listing to determine whether their products require a Proposition 65 warning, to provide a warning as a precautionary measure or to update their current warning, if necessary, to reflect the new listing. The state listed “marijuana smoke” as a carcinogen in 2009.
Effect of THC Listing on Cannabis Products That Are Not Smoked or Vaped, Such as Marijuana Edibles
Businesses that currently manufacture and sell these products without a warning will need to provide a warning reflecting the THC listing unless they determine their products are exempt. Most businesses will likely provide a warning as a precautionary measure without making this determination. OEHHA has not yet adopted a “safe harbor” exposure level for THC (below which a product would not require a warning), but even when it does, exemption determinations can be complicated and potentially expensive.
Depending on the type of product, precautionary warnings are usually a good idea anyway because only a warning will protect a business against enforcement. Proposition 65 private enforcers regularly target exempt products because Proposition 65 places the burden on businesses rather than on the enforcers to prove a particular product does not require a warning. Warnings would also protect cannabis products that may contain other chemicals on the list, such as naturally occurring metals.
Effect of Both Listings on Cannabis Products That Are Smoked or Vaped
Businesses that currently manufacture and sell these products with a warning for the 2009 marijuana smoke carcinogen listing may need to update their warning, depending on how their current warning is worded. For example, if their current warning reflects only one chemical (marijuana smoke) and the carcinogen endpoint, the warning will need to be updated to reflect another chemical (THC) as well as the reproductive harm endpoint (for marijuana smoke and THC), as shown in the examples below.
Businesses that currently provide one of the following warnings will not need to update their warnings. These warnings will remain compliant for the reasons explained below.
This “short-form” warning will remain compliant because it does not require that specific chemicals be identified, and because it includes both toxicity endpoints.
- WARNING: This product can expose you to chemicals including marijuana smoke, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
This “long-form” warning will remain compliant because, by using the language “chemicals including,” it references more than one listed chemical, and because it includes both the cancer and reproductive harm endpoints.
This warning will also remain compliant because a long-form warning must identify at least one listed chemical for each endpoint (if relevant to the product), but if the identified chemical is listed for both endpoints, then only that chemical needs to be identified. Marijuana smoke is now listed for both endpoints, so THC (and other listed chemicals, if relevant) does not need to be identified unless a business chooses to do so.
‘Marijuana Smoke’ or ‘Cannabis (Marijuana) Smoke?’
Although it would be a good idea eventually to update current warnings like the one above that includes the 2009 “marijuana smoke” term, these warnings should remain compliant indefinitely. OEHHA has not indicated otherwise, although it appears from recent references on its website that it may eliminate the old term and list both endpoints as “cannabis (marijuana) smoke.”
Effect of THC Listing on Products Containing Hemp-Derived CBD
In the absence of a Proposition 65 safe harbor exposure level for THC, it is unclear whether products containing CBD derived from hemp cultivated pursuant to California’s and the federal government’s legal limit of 0.3% or less THC on a dry weight basis would be exempt from Proposition 65 warnings. It would be difficult, however, for a private enforcer to claim a product that is compliant with the strict state and federal THC limit violates Proposition 65 on the basis that it exposes consumers to a level of THC requiring a warning when OEHHA has not yet established that level.
 See Cal. Health & Safety Code § 25249.10(b).
 See Cal. Health & Safety Code § 25249.10(c).
 See generally 27 Cal. Code Regs. § 25603 (“Clear and Reasonable Warnings;” “Safe Harbor Methods and Content”).
 A short-form warning may be provided on a product or on its packaging, but when a warning is provided in another manner, such as on a retail sign, it must be in the “long form” shown above. See id. §§ 25600.1(i), 25602(a)(4), 25603(b).
 See Cal. Food and Agricultural Code § 81000(a)(6); Cal. Health & Safety Code §§ 11018, 11018.5; Agriculture Improvement Act of 2018 (Farm Bill), 7 U.S.C §1639o(1).