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California Heavy Metals Testing for Cannabis May Usher New Prop 65 Claims

The California Bureau of Cannabis Control (CBCC) regulations require cannabis and cannabis products to undergo mandatory testing for certain chemicals. Beginning on December 31, 2018, the mandatory testing will include testing for the following heavy metals: lead, cadmium, arsenic, and mercury. The California Code of Regulations (CCR) prescribe the process for heavy metals testing. It provides that samples of cannabis or cannabis products should be analyzed to determine the existence of heavy metals and that the result will be reported as a pass or fail. A sample “passes” the heavy metal test if it does not exceed the action levels provided in the CCR, and a “pass” result means that the cannabis product may be sold at retail. Conversely, a sample that “fails” will result in a batch that is not available for retail sale.

However, a “pass” result under the cannabis regulations does not necessarily mean that the tested product meets Proposition 65 requirements. For one thing, the cannabis actions levels are expressed as a concentration. In contrast, the Proposition 65 warning triggers are expressed as a dose. For example, the cannabis action level for lead is 0.5 micrograms per gram; the Proposition 65 warning level for lead is 0.5 micrograms per day. While the numbers look the same – each value is 0.5 – the units used under the separate regulatory programs are vastly different: it’s like comparing apples and oranges. This could presumably result in the incongruous situation where cannabis and cannabis products are sold or distributed in accordance with the regulations governing chemical exposure under the cannabis regulations, but still exceed threshold levels for heavy metals under California law, thereby prompting a Proposition 65 warning.

Heavy metals, especially lead, are a favored target of Proposition 65 enforcement actions because their warning levels are so low. That, combined with the perception in the Proposition 65 enforcement community that all cannabis businesses have deep pockets, means that heavy metals mandatory testing requirements for cannabis may incite a new wave of Proposition 65 claims.

Worse, this scenario could cause an evidentiary problem for cannabis dispensaries or manufacturers that are defending against allegations of violating Proposition 65. The test reports required to be generated under the cannabis testing regulations may be used as purported evidence that a Proposition 65 defendant “knew” that it was causing exposures to heavy metals in cannabis.

Those in the cannabis industry in California will be forced to grapple with complying with cannabis law without further exposing themselves to Proposition 65 enforcement litigation. It is critical that cannabis businesses review their test reports and Certificates of Analysis not only to evaluate compliance with the cannabis regulations, but also to evaluate their potential obligations under Proposition 65.

Grimaldi Law Offices has been advising clients for over 20 years on chemical and product law. For knowledgeable advice and in-depth analysis on your Prop 65 compliance obligations, contact Grimaldi Law Offices at (415) 463-5186 or email us at [email protected].


Ms. Grimaldi maintains a diverse environmental law practice focusing on chemical and product regulation and litigation defense. Her practice areas include Proposition 65, California's Safer Consumer Products Regulations, California's Rigid Plastic Packaging Container Act and the federal Toxic Substances Control Act. Ms. Grimaldi graduated from the University of California Hastings College of the Law magna cum laude and holds a Bachelor of Science Degree in Bacteriology from University of California, Davis. Prior to attending law school, she worked as a research assistant in laboratories at the University of California, San Francisco Cancer Research Institute and at the University of California, San Francisco School of Medicine.