Latest Prop 65 Challenge Targets DEA After Series of Industry Wins
A cosmetics industry trade group is asking the Eastern District of California to enjoin a Proposition 65 warning for diethanolamine (DEA), arguing that the compelled labeling requirement violates the First Amendment.
The suit was filed March 2, 2026, by the Personal Care Products Council (PCPC). It follows a string of court victories challenging other Prop 65 warning requirements for chemicals including glyphosate, acrylamide, and titanium dioxide, the last of which was also brought by PCPC.
DEA was automatically added to the Prop 65 list after the International Agency for Research on Cancer (IARC) concluded that the substance is “possibly carcinogenic to humans.” However, PCPC argues that IARC was unable to find a single study establishing a link between DEA and cancer in humans, instead basing the determination on a study of “questionable relevance” in a highly susceptible strain of mice. Other regulatory bodies, like FDA and EPA, have not reached the same conclusion, and some have “expressed skepticism” about the mouse study, PCPC argues.
“Indeed, no California agency has made any scientific determination as to whether DEA causes cancer in humans. Nor has any federal agency done so,” the complaint states.
According to PCPC, laws regulating commercial speech are typically subject to intermediate scrutiny, with a more lenient standard for purely factual and noncontroversial disclosures. However, because the “cancer warning requirement as applied to DEA in cosmetic and personal products is false, misleading, and factually controversial, it cannot survive any level of constitutional scrutiny” and therefore violates the First Amendment, the complaint alleges.
PCPC argues that the warning requirement effectively forces companies to choose between “conveying the unsubstantiated message that DEA in cosmetic products increases cancer risk in humans” or facing “a significant and imminent risk of an enforcement action.” Although an exception exists for products that do not present significant risk, the complaint notes that companies must be able to prove that defense in court if challenged, a costly and uncertain process that leads many to “acquiesce and provide a warning” even if they believe it is inaccurate.
PCPC also claims that, since the warning requirement took effect in 2013, hundreds of companies manufacturing or selling personal care products have paid over $7 million in settlements with private enforcers.
The trade association seeks a declaration that the warning is unconstitutional as applied to personal care products and a permanent injunction barring enforcement by California or private parties.
The case is The Personal Care Products Council v. Bonta, No. 26-cv-682 (E.D. Cal.), filed 3/2/26.
