Legalization of medicinal and adult-use cannabis in California has fomented a surge of seed-to-sale companies angling to lure market share from a sea of customers. The water may soon be agitated, however, by the Office of Environmental Health Hazard Assessment (OEHHA). OEHHA is the lead California agency that oversees implementation of Proposition 65, formally known as the Safe Drinking Water and Toxic Enforcement Act of 1986. OEHHA recently announced that it has selected cannabis (marijuana), marijuana (cannabis) smoke, cannabis extracts, and delta-9-Tetrahydrocannabinol (THC) for review for possible listing under Proposition 65 as chemicals that cause reproductive toxicity. If the Developmental and Reproductive Toxicant Identification Committee (DARTIC) determines that these chemicals cause reproductive toxicity based upon "scientifically valid testing according to generally accepted principles," marijuana in its various forms will likely join a list of more than 900 chemicals known to the state to cause cancer, birth defects, or other reproductive harm. Companies that cultivate, distribute, and/or sell marijuana and products containing marijuana in California would then be required to warn consumers—and possibly employees and passersby—that exposure to these listed chemicals can cause reproductive harm.

This is not the first time that OEHHA has raised public health concerns regarding marijuana. In June 2009, marijuana smoke was listed as a cancer-causing chemical under Proposition 65. (Interestingly, no public comments were submitted in response to the proposed listing.) Ever since, dispensaries have largely been targeted in enforcement actions for failing to warn about exposure to marijuana smoke. If past is prologue, then the cannabis industry is on notice that regulation of marijuana in California is not just limited to the Medicinal and Adult-Use Cannabis Regulation and Safety Act. A decision to list marijuana and its various forms will require cannabis businesses across the chain of commerce to provide "clear and reasonable" warnings in compliance with Proposition 65 requirements. Failure to warn will lead to enforcement, often brought through private lawsuits, which may lead to imposition of civil penalties, injunctive relief, and payment of attorneys' fees (which can be steep).

One might raise an eyebrow at OEHHA's announcement, as there is a widespread belief that marijuana alleviates various ailments such as chronic pain. Indeed, cannabidiol, also known as CBD, is recognized for treating a host of medical problems. (CBD oil and other CBD products fall into the category of a cannabis extract, which is subject to potential listing under Proposition 65. It is unclear whether OEHHA would treat hemp-derived CBD differently from marijuana-derived CBD; hemp and marijuana are both varieties of the cannabis plant, but only marijuana has psychoactive properties.) Nevertheless, if these chemicals are added to the Proposition 65 list, potential customers that read the warning labels may think twice before purchasing products containing marijuana.

From March 15 through April 29, 2019, the public has an opportunity to provide OEHHA with scientific information relevant to whether marijuana, marijuana smoke, cannabis extracts and THC cause reproductive toxicity. OEHHA will review and consider the information received as it develops hazard identification materials for these chemicals. The hazard identification materials will be made available for public comment, and the comments will be sent to the DARTIC for consideration. The DARTIC will then hold a public meeting, tentatively planned for Fall 2019, at which point the chemicals will be considered for listing under Proposition 65.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.