First Amendment Milestone: Federal Court Bars California Prop 65 Cancer Warnings for Diethanolamine (DEA)

by | Oct 13, 2026 | California Cosmetic Regulations, U.S. Regulatory

In a landmark decision for cosmetic and personal care manufacturers, a federal court in Sacramento has permanently prohibited the State of California from enforcing Proposition 65 cancer warning mandates for products containing the common surfactant diethanolamine (DEA). The ruling, handed down by Judge Daniel Calabretta of the U.S. District Court for the Eastern District of California, represents the latest constitutional setback for Proposition 65 enforcement and reinforces judicial skepticism toward state-mandated consumer warnings lacking firm scientific consensus.

Judicial Ruling and Constitutional Grounding:

The court’s decision turns squarely on First Amendment commercial speech protections:

  • The court ruled that based on the current state of scientific evidence, compelling brands to place cancer warnings for DEA cannot be constitutionally enforced. 
  • Because the premise that DEA poses a carcinogenic risk to humans is contested rather than purely factual and uncontroversial, mandatory warning statements amount to unconstitutionally compelled commercial speech.
  • PCPC filed the initial legal challenge in March 2024, maintaining that requiring warning statements claiming DEA is “known to the State of California to cause cancer” infringes upon commercial First Amendment rights

Industry Context: A Growing Pattern of First Amendment Victories:

This injunction marks a major milestone in a continuous series of successful First Amendment challenges brought by industry against Proposition 65 warning requirements where the underlying toxicology remains debated: 

  • The DEA ruling follows successful federal court challenges restricting mandatory cancer warnings for glyphosate, acrylamide, and titanium dioxide (in cosmetic formulations). 
  • Courts continue to reject compelled health warnings where authoritative scientific reviews fail to demonstrate a clear, uncontroverted link between consumer exposure and human carcinogenicity.
  • While the permanent injunction blocks current enforcement, the state Attorney General retains the statutory ability to petition the court to dissolve the injunction should new scientific evidence establish consensus or if governing legal standards shift.

Strategic Implications and Action Items for Personal Care Brands:

While the ruling provides immediate regulatory relief, legal and regulatory specialists urge companies to approach their compliance strategies with measured caution:

  • Audit existing product formulations containing DEA, identify any pending 60-day notices of violation, and evaluate ongoing enforcement threats involving the ingredient. 
  • Review master product labels and supply chain compliance documentation concerning DEA to determine whether warning removals or revisions are commercially warranted.

If you need assistance with formulation or label reviews, contact us.