Ninth Circuit Finds That Compelled Speech Doctrine Bars Proposition 65 Cancer Warnings for Herbicides

In a major development under California’s Proposition 65 (Prop 65), the U.S. Court of Appeals for the Ninth Circuit held that California cannot require carcinogen warnings for exposures to glyphosate, a chemical commonly used in herbicides. This development follows a similar Ninth Circuit decision issued last year regarding exposures to acrylamide in food. These decisions suggest that many more companies could have grounds to challenge Prop 65 warnings applicable to their products.

Prop 65 is California’s unique right-to-know law that requires companies to provide a warning before exposing consumers to a chemical known to the state to cause cancer, birth defects, or other reproductive harm. The list of chemicals covered by Prop 65, available to the public, has grown to over 1,000, including those found in pesticides, household products, food, drugs, and dyes. Penalties for failing to provide the required notice can be up to $2,500 per violation per day, which can add up to significantly large sums. Prop 65 has been widely criticized for requiring warnings even when the scientific evidence is weak and in situations where the chemical is not present in amounts that would be carcinogenic. Practically speaking, Prop 65 creates an “over-warning” problem: The law requires warnings for so many products and situations that the warnings themselves become meaningless.

As relevant to the case at hand, in 2015, the International Agency for Research on Cancer (IARC) identified glyphosate as “probably carcinogenic” to humans based on limited evidence in humans and studies done on animals, including worms, fish, and reptiles. Because substances determined to be carcinogenic by the IARC are required to appear on the Proposition 65 list, glyphosate was added to the list in 2017, even though the U.S. Environmental Protection Agency (EPA), the California Office of Environmental Health Hazard Assessment (OEHHA), and all other regulatory and governmental bodies to have considered the question had found it unlikely to be carcinogenic.

A coalition of agricultural producers and business entities — entities that sell glyphosate-based herbicides, use glyphosate to cultivate their crops, or process such crops into foods sold in California — filed suit to enjoin the California Attorney General from enforcing Prop 65’s warning requirement for glyphosate on the ground that it violated their First Amendment rights to be free from compelled speech. The district court agreed with these plaintiffs and issued a permanent injunction against such enforcement. On November 6, 2023, the Ninth Circuit affirmed the district court’s broad injunction in a 2-1 decision, National Association of Wheat Growers v. Bonta.¹

Prop 65’s warning requirements are analyzed under the Supreme Court’s First Amendment compelled commercial speech doctrine. The key question in this case was what level of scrutiny applied to Prop 65’s glyphosate warning. Most instances of compelled commercial speech must survive intermediate scrutiny, meaning the government must show that the compelled speech directly advances a “substantial” government interest and is not “more extensive than necessary.” However, there is an exception where the compelled commercial speech is “purely factual and uncontroversial information,” and a lower standard applies that requires the compelled speech to be only “reasonably related” to a substantial government interest and not “unjustified or unduly burdensome.”

The Ninth Circuit recognized the unresolved scientific debate over glyphosate’s carcinogenicity and that the IARC is the only regulatory or governmental body to conclude that glyphosate is probably carcinogenic. While the Attorney General and OEHHA had offered several versions of a Prop 65 warning for glyphosate, the Ninth Circuit held that the offered warnings were neither purely factual nor uncontroversial but instead misleading in that they all conveyed “the overall message that glyphosate is unsafe which is, at best, disputed.” As a result, the lower standard of review did not apply, and instead the Ninth Circuit held that intermediate scrutiny applied to Prop 65’s glyphosate warning.

Applying intermediate scrutiny, the Ninth Circuit recognized that California has a substantial interest in preserving the health of its citizens. However, it held that “compelling sellers to warn consumers of a potential ‘risk’ never confirmed by any regulatory body — or of a hazard not ‘known’ to more than a small subset of the scientific community — does not directly advance that interest.” Moreover, the Ninth Circuit noted that California had various other ways it could promote its view that glyphosate is a carcinogen without compelling the plaintiffs’ speech, such as through its own website or advertising campaigns.

Prop 65’s incredibly extensive list likely contains many chemicals like glyphosate for which there is no clear scientific consensus on their carcinogenic or reproductive risks. This decision opens up the possibility of future successful challenges to compelled disclosures as to those chemicals as well. And the logic of this decision may support challenges to compelled warnings in other contexts. 

¹No. 20-16758 (9th Cir. Nov. 7, 2023).