The US District Court for the Eastern District of California on May 2, 2025 granted summary judgment in favor of the California Chamber of Commerce, holding that Proposition 65 warning requirements for acrylamide in food products violate the First Amendment. The ruling follows an earlier preliminary injunction and now permanently bars the state – and private enforcers – from requiring Proposition 65 warnings for food products containing acrylamide.

The decision has broad implications for compelled commercial speech under California’s toxics warning law. We examine the key takeaways.

Case overview

The court held that California’s required warning – that consuming acrylamide-containing food may increase cancer risk – fails to meet the “purely factual and uncontroversial” standard set out in Zauderer v. Office of Disciplinary Counsel, 471 U.S. 626 (1985). Because the warning conveys a disputed message not supported by scientific consensus, the court applied the more demanding Central Hudson test and found the warning unconstitutional.

In reaching that conclusion, the court emphasized the critical distinction between “hazard” and “risk” – a nuance often lost in Proposition 65 enforcement. While acrylamide has been shown to cause cancer in laboratory animals at high doses, the court noted that “dozens of epidemiological studies of acrylamide in human diets have not clearly shown an increased risk of cancer in humans.” The court concluded that California’s mandated warning failed to reflect that nuance, and instead communicated a conclusive, misleading message.

Key implications

This ruling adds to a growing line of decisions rejecting Proposition 65 warning mandates where the science is unsettled, or the warning overstates the risk. This decision follows the Ninth Circuit’s ruling in National Association of Wheat Growers v. Bonta (9th Cir. 2023), which found Proposition 65 warnings for glyphosate unconstitutional, and builds on Personal Care Products Council v. Bonta (E.D. Cal. 2024), where DLA Piper co-represented the Personal Care Products Council in its successful effort to obtain a preliminary injunction on First Amendment grounds barring new lawsuits alleging failure to warn for titanium dioxide.

Looking ahead

While the recent ruling is limited to acrylamide in food, it highlights the constitutional vulnerability of Proposition 65 warnings where scientific disagreement persists – particularly for chemicals listed under the “Labor Code Mechanism,” by which substances classified merely as “possibly carcinogenic” by the International Agency for Research on Cancer (IARC) are nonetheless listed as “known” carcinogens under Proposition 65.

Businesses facing warning obligations for substances like acrylamide, titanium dioxide, or other chemicals with possible health risks that remain subject to scientific debate are encouraged to revisit their compliance strategies in light of these precedents and consider whether such compelled warnings may now be vulnerable.

For more information or assistance with acrylamide, titanium dioxide, or other Proposition 65 matters, please contact the authors or DLA Piper’s Proposition 65 team.