Cannabis Smoke and THC Listed on Proposition 65 for Reproductive Toxicity

On January 3, 2020, cannabis (marijuana) smoke and delta-9-tetrahydrocannabinol (Δ9-THC) were added to the Proposition 65 list of chemicals known to the state of California to cause reproductive toxicity based on the developmental endpoint (OEHHA 2020a). The listing came from California’s Developmental and Reproductive Toxicant Identification Committee (DARTIC), who serve as the state’s qualified experts (SQE). Cannabis smoke, which is produced from burning cannabis plants, has been listed as a Proposition 65 carcinogen since 2009, and has been the source of over one hundred 60-day notices. Cannabis smoke contains thousands of chemicals, including the potent and psychoactive cannabinoid Δ9-THC, which is also found in cannabis plants (OEHHA 2019). After reviewing the scientific literature, DARTIC determined evidence of development toxicity from prenatal and early-life exposures to cannabis smoke and Δ9-THC (OEHHA 2019).

The new listing may have a significant impact on cannabis product manufacturers, distributors, and consumers. Businesses will have one year to add or update warnings on their cannabis products in order to comply with the new Proposition 65 listing (OEHHA 2020b). Although some businesses may already have Proposition 65 warnings on their products regarding cancer, this new listing will likely require companies to amend these warnings to specifically address reproductive toxicity. Further, companies that manufacture or distribute cannabis products that are not inhaled but contain Δ9-THC, such as edibles or similar products, will need to now consider warnings regarding reproductive toxicity.

Cardno ChemRisk has assisted companies in understanding potential product exposures and risks. Our scientists have evaluated diverse scenarios ranging from a single product to entire product lines for Proposition 65 compliance. We provide screening level testing plan advice and assistance, screening or refined exposure assessments, and acceptable risk level calculations. For more information regarding Cardno ChemRisk’s Proposition 65 capabilities, please contact Ms. Jennifer Bare or Dr. Ania Urban.