A Federal District Court in California has ruled that Proposition 65 warning requirements for dietary acrylamide are unconstitutional. The California Chamber of Commerce (“CalChamber”) sued five years ago challenging the statewide requirement under Proposition 65 for warning labels on foods containing acrylamide. (California Chamber of Commerce v. Bonta, No. 2:19-cv-02019-DJC-JDP.) This ruling is a major victory for CalChamber and the latest chapter in its long battle with the California Attorney General and private enforcer Council for Education and Research on Toxics (“CERT”) over whether a warning can be required by the State in light of the disputed science around acrylamide.
What is Proposition 65?
Prop 65, also known as the Safe Drinking Water and Toxic Enforcement Act, requires businesses that sell products into California to provide warnings about significant exposures to chemicals known to cause cancer, birth defects, or reproductive harm. These substances can be present in consumer goods, food and beverages, residential environments, workplaces, or the environment.
What is Acrylamide?
Acrylamide is a substance that forms through a natural chemical reaction in certain plant-based foods during high-temperature cooking and can be found in foods like potato chips, bread, grilled vegetables, nuts, crackers, and olives. Although studies exposing laboratory rats and mice to high levels of acrylamide have been shown to produce cancer, other studies have found no consistent evidence that dietary acrylamide increases the risk of cancer in humans.[1]
The Original Warning
Prior to the initiation of the CalChamber lawsuit, if a product contained acrylamide, companies were required to provide what is now referred to as the “Original Warning”:
WARNING: Consuming this product can expose you to chemicals including acrylamide, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov/food.
In 2019, CalChamber brought suit alleging that forcing businesses to provide warnings stating that acrylamide in food is known to cause cancer violates its members’ First Amendment rights because the scientific evidence on acrylamide’s carcinogenicity is in dispute. In 2020, CalChamber sought a preliminary injunction to stop the enforcement of this warning obligation. The district court granted the injunction in March 2021, noting that the scientific debate over acrylamide’s cancer risk remains unresolved.
The Alternative Warning & New Warnings for Acrylamide
While the CalChamber litigation was pending, the California Office of Environmental Health Hazard Assessment (OEHHA) adopted an “Alternative Warning” for acrylamide, which would allow companies to obtain safe harbor protection with the following language beginning January 1, 2023:
Consuming this product can expose you to acrylamide, a probable human carcinogen formed in some foods during cooking or processing at high temperatures. Many factors affect your cancer risk, including the frequency and amount of the chemical consumed. For more information including ways to reduce your exposure, see www.P65Warnings.ca.gov/acrylamide.
CERT and the California Attorney General argued that the Alternative Warning mooted the CalChamber litigation, while CalChamber argued that the new regulation was still misleading based on the conflicting evidence regarding acrylamide’s effects.
In November 2023, OEHHA adopted additional alternative warning language for acrylamide (referred to as the “New Warning”) effective January 1, 2025, which allowed businesses to select amongst several qualifying statements to be included in their Prop 65 warnings:
- The International Agency for Research on Cancer has found that acrylamide is probably carcinogenic to humans.
- The United States Environmental Protection Agency has found that acrylamide is likely to be carcinogenic to humans.
- The United States National Toxicology Program has found that acrylamide is reasonably anticipated to cause cancer in humans.
- Acrylamide has been found to cause cancer in laboratory animals. Many factors affect your cancer risk, including the frequency and amount of the chemical consumed.
- For more information including ways to reduce your exposure, see www.P65Warnings.ca.gov/acrylamide.
Cal. Code Regs. tit. 27, § 25607.2(c)(2).
What was the Court’s Ruling on Summary Judgment?
CalChamber continued to pursue its case even after the New Warning was adopted, arguing that none of the safe harbor warnings—the Original, Alternative, or New Warning—meet constitutional standards because they compel a message that remains scientifically controversial. After oral argument on February 12, 2025, the district court granted summary judgement in favor of CalChamber, holding that the Prop 65 warning requirement for dietary acrylamide is controversial due to the lack of scientific consensus and unnecessarily burdens businesses by compelling them to convey disputed scientific information.
First applying the Zauderer[2] test, the district court found that the warning was neither uncontroversial nor purely factual because there is no scientific consensus that dietary acrylamide poses a human cancer risk. (Cal. Chamber of Commerce v. Bonta, No. 2:19-cv-02019-DJC-JDP, at 18:13-16 (E.D. Cal. 2024)) The district court acknowledged that, while some scientific authorities classify acrylamide as a likely carcinogen, “authorities such as the FDA and the National Cancer Institute have questioned whether there is sufficient proof that dietary acrylamide is a cancer risk to humans.” (Id. at 22:3-6.) Although the law does not require complete consensus among the scientific community before a warning may be required, the district court found that the “New Warning” is “not purely factual and uncontroversial.” (Id. at 15:16-20.)
The district court next applied the Central Hudson[3] test, finding that the California Attorney General failed to show that the “New Warning” directly advanced the government’s interest and was not more extensive than necessary to achieve that interest. (Id. at 26:7-9.) The district court pointed out that there were less burdensome alternatives available for the State to achieve its objectives, such as posting information on the Internet or conducting advertising campaigns educating consumers. (Id. at 26: 14-22.)
Ultimately, the district court concluded that the Prop 65 safe harbor warning requirement for dietary acrylamide violates the First Amendment because it “burdens the free speech of businesses” and forces businesses to communicate a particularly controversial and disputable message about the carcinogenic risk associated with dietary acrylamide. (Id. at 26:14-16.) As a result, the district court issued a permanent injunction enjoining both the California Attorney General and all private enforcers from enforcing the acrylamide warning requirements. The California Attorney General filed a notice of appeal on June 2, 2025. With the appeal now pending, it is clear that this case is far from over and there is more to come.
FOOTNOTES
[1] See Acrylamide and Cancer Risk – NCI and Acrylamide | FDA
[2] Zauderer v. Office of Disciplinary Counsel of Supreme Court of Ohio, 471 U.S. 626, 651 (1985).
[3] Central Hudson Gas & Electric Corp. v. Public Service Commission of New York, 447 U.S. 557 (1980).