Federal Court Enjoins Proposition 65 Enforcement for Diethanolamine

On June 24, 2026, Judge Daniel J. Calabretta of the U.S. District Court for the Eastern District of California entered a final judgment and permanent injunction in The Personal Care Products Council (PCPC) v. Rob Bonta.

Under the terms of the injunction, to which the California attorney general stipulated, the state and all private enforcers are permanently enjoined from bringing Proposition 65 enforcement actions or issuing 60-day notices for an alleged failure to warn regarding exposures to diethanolamine (DEA) in cosmetic and personal care products. 

Background on DEA enforcement

The Office of Environmental Health Hazard Assessment (OEHHA) added DEA to the Proposition 65 list of carcinogens in 2012. The listing was mandated by the statutory Labor Code mechanism after the International Agency for Research on Cancer (IARC) classified the chemical as a Group 2B "possible human carcinogen." Although enforcement remained low for over a decade, 60-day notices targeting DEA experienced a sharp surge, rising from fewer than 100 notices in 2023 to more than 1,000 notices in 2024. These claims primarily focused on personal care items and cosmetics, such as shampoos, soaps, lotions, and makeup products.

The constitutional challenge

In response to the litigation spike, PCPC filed a federal lawsuit on March 3, 2026, alleging that the required Proposition 65 cancer warning for DEA violates the First Amendment. PCPC argued that forcing businesses to state that DEA is "known to cause cancer" compels misleading speech, as mainstream scientific organizations categorize the chemical only as a possible carcinogen, not a known human carcinogen. The attorney general ultimately stipulated to the permanent injunction rather than litigating the case to trial. 

This outcome aligns with a recent series of successful First Amendment challenges to Proposition 65 warning mandates. Specifically, the U.S. District Court for the Eastern District of California previously invalidated the warning requirement for glyphosate in National Association of Wheat Growers v. Bonta. Federal district courts have similarly enjoined mandated warnings for acrylamide in food products (California Chamber of Commerce v. Bonta) and for titanium dioxide in cosmetics (Personal Care Products Council v. Bonta).

Takeaways

• The state and private plaintiffs are immediately prohibited from filing Proposition 65 lawsuits or prosecuting existing claims involving DEA exposures.
• This federal injunction provides an absolute defense against any legacy notices regarding DEA in cosmetic and personal care products.

If you have any questions concerning the developments discussed in this Update, please contact members of Perkins Coie’s Food & Consumer Packaged Goods Litigation team.