- On March 2, 2026, the Personal Care Products Council (PCPC) filed a lawsuit in federal court challenging California’s Proposition 65 cancer warning requirement for diethanolamine (DEA). Proposition 65 is a California law that requires businesses to provide warnings before exposing consumers to chemicals the state has listed as causing cancer or reproductive harm; listings can be based on determinations from outside scientific bodies such as the International Agency for Research on Cancer (IARC).
- PCPC argues that the DEA warning requirement violates the First Amendment by compelling companies to convey a false and misleading message. OEHHA listed DEA as a carcinogen in 2012 under the labor code mechanism because IARC classified it as “possibly carcinogenic to humans” based largely on a single mouse study. According to the lawsuit, a parallel rat study showed no cancer link, and IARC identified no evidence of carcinogenicity in humans.
- Despite this limited evidence, more than 1,400 Prop. 65 notices have been filed alleging failures to warn for DEA in a broad range of personal care products, with enforcement activity rising sharply in 2024. PCPC contends that businesses must now provide cancer warnings even though no agency has determined DEA to be a known human carcinogen. The Attorney General’s office has not commented.
- The challenge follows a series of successful First Amendment suits targeting Prop. 65 warnings for glyphosate, acrylamide, and titanium dioxide. Nearly 40 DEA‑related Prop. 65 cases are currently consolidated in Alameda County Superior Court, and OEHHA’s proposed safe harbor level for dermal exposure, 6.4 micrograms per day, remains under review.
- Keller and Heckman will continue to monitor developments related to Proposition 65.