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Circuit Court Affirms Barring Proposition 65 Warning for Glyphosate

Legal books, gavel, and laptop

The U.S. Court of Appeals for the Ninth Circuit ruled on November 7, 2023, that California cannot require cancer warning labels for glyphosate under Proposition 65. The ruling, in National Association of Wheat Growers et al. v. Rob Bonta et al., Case Number 20-16758, affirms the district court’s grant of summary judgment in favor of the plaintiffs and its entry of a permanent injunction enjoining the California Attorney General from enforcing Proposition 65’s carcinogen warning requirement for the herbicide glyphosate.

In 2015, IARC identified glyphosate as “probably carcinogenic” to humans. As a result, the California Office of Environmental Health Hazard Assessment (OEHHA) listed glyphosate as a chemical known to the state of California to cause cancer on July 7, 2017, with the warning requirement to take effect on July 7, 2018.

The plaintiffs first sued California over the glyphosate warning in November 2017, alleging it violated their First Amendment rights to be free from compelled speech that is not purely factual and non-controversial. In February 2018, the U.S. District Court for the Eastern District of California enjoined the State from enforcing the warning requirement. The court explained that the safe harbor warning language stating that glyphosate is “known to the state of California to cause cancer,” could mislead the average consumer, as “[i]t is inherently misleading for a warning to state that a chemical is known to the state of California to cause cancer based on the finding of one organization . . . when apparently all other regulatory and governmental bodies have found the opposite.”
Plaintiffs then sought an injunction barring enforcement of the Proposition 65 warning as to glyphosate. On June 22, 2020, the District Court issued an injunction concluding, “[a]s plaintiffs have prevailed on the merits of their First Amendment claim, are likely to suffer irreparable harm absent an injunction, and have shown that the balance of equities and public interest favor an injunction, the court will grant plaintiffs’ request to permanently enjoin Proposition 65’s warning requirement as to glyphosate.” (See National Association of Wheat Growers et. al. v. Xavier Becerra, Case Number 2:17-cv-02401.)

California has offered several alternative versions for the glyphosate warning. Most recently, on September 8, 2022, the State issued the following Safe Harbor Regulation for Exposures to Glyphosate from Consumer Products. The required glyphosate warning included the words, “Using this product can expose you to glyphosate. The International Agency for Research on Cancer classified glyphosate as probably carcinogenic to humans. US EPA has determined that glyphosate is not likely to be carcinogenic to humans; other authorities have made similar determinations. A wide variety of factors affect your potential risk, including the level and duration of exposure to the chemical. For more information, including ways to reduce your exposure, go to”

In the November 2023 ruling, the panel concluded that “the Prop 65 warning as applied to glyphosate—in any form that has been presented to this Court—is not purely factual and uncontroversial, and thus is subject to intermediate scrutiny. Because the Attorney General fails to meet that standard, we affirm the district court’s grant of summary judgment and entry of a permanent injunction.” Further explaining, the panel wrote, “[b]ecause none of the proposed glyphosate Prop 65 warnings are narrowly drawn to advancing California’s interest in protecting consumers from carcinogens, and California has less burdensome ways to convey its message than to compel Plaintiffs to convey it for them, the Prop 65 warning as applied to glyphosate is unconstitutional.”