Most companies I work with who do business in California have little good to say about California's Proposition 65 law. It requires businesses that sell products into California to provide warnings about exposures to chemicals known to cause cancer, birth defects, or reproductive harm. These substances are present everywhere, in consumer goods, food and beverages, residential environments, workplaces, or the environment. Complying with the law is a challenge, because California seems to classify an abundance of chemicals as cancer risks, thereby necessitating a Proposition 65 warning.

Acrylamide is one such chemical. It is a substance that forms through a natural chemical reaction in certain foods during high-temperature cooking, like potato chips, bread, nuts, and crackers. Although some studies exposing laboratory rats and mice to high levels of acrylamide have shown it to cause cancer, other studies have found no evidence that acrylamide in these foods increases the risk of cancer in humans.

The California Office of Environmental Health Hazard Assessment (OEHHA) adopted a warning for acrylamide based upon the conclusion by certain authoritative bodies that classified the chemical as a "probable carcinogen." This conclusion was accepted over the conclusion of other authoritative bodies, such as the Food and Drug Administration, that dietary exposure to acrylamide does not cause cancer. The California Chamber of Commerce brought a lawsuit challenging the statewide requirement that foods containing acrylamide include a Proposition 65 warning.

On May 2, 2025, the US District Court for the Eastern District of California found in favor of the California Chamber of Commerce and declared the warning unconstitutional. In reaching that conclusion the court emphasized the distinction between “hazard” and “risk” – a nuance often lost in Proposition 65 enforcement. The court noted that the authoritative bodies were not in alignment on the cancer risk of acrylamide in food. Further, the court noted that classifying a chemical such as acrylamide as a “probable” carcinogen is misleading because it implies a cancer risk from food consumption without scientific consensus. Because California’s mandated warning was a misleading message, it was found to be unconstitutional.

While the ruling is limited to acrylamide in food, it highlights the constitutional vulnerability of Proposition 65 warnings where scientific disagreement exists. It could indicate future challenges to Proposition 65 warning requirements where scientific consensus is lacking. This would be a welcome sea-change for companies – particularly in the food and beverage space – doing business in California.