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June 20, 2024

California Court Grants Injunction to Stop Prop 65 Warnings for Titanium Dioxide in Cosmetic and Personal Care Products

The ACTA Group

On June 12, 2024, the U.S. District Court for the Eastern District of California (District Court) issued an Order granting a preliminary injunction brought by the Personal Care Products Council (PCPC), which alleged that the California Office of Environmental Health Hazard Assessment’s (OEHHA) requirement for warnings under Proposition 65 (Prop 65) related to titanium dioxide in cosmetics and personal care products violated the First Amendment. The Personal Care Products Council v. Bonta, No. 2:23-cv-01006-TLN-JDP (E.D. Cal. 2024). In its Order, the District Court enjoined the California Attorney General and any private citizen enforcers from enforcing Prop 65’s warning requirement for “cancer as applied to Listed Titanium Dioxide (i.e., titanium dioxide that consists of airborne, unbound particles of respirable size) in cosmetic and personal care products.” The District Court also denied a motion to intervene by Environmental Health Advocates, Inc. (EHA), who had argued it was “an interested party because it is the primary enforcer of Prop 65.”

This is the third case successfully challenging Prop 65 warnings on First Amendment grounds, with previous cases involving glyphosate and acrylamide, as discussed in our FIFRA blog. See Natl. Assoc. of Wheat Growers v. Bonta, 85 F.4th 1263 (9th Cir. 2023); Cal. Chamber of Comm. v. Bonta, 529 F. Supp. 3d 1099 (E.D. Cal. 2021). These are important cases with implications for companies facing Prop 65 warning requirements for other substances where the underlying scientific basis for listing also may be unclear and controversial.


Listed Titanium Dioxide has been on the Prop 65 list since 2011, based on the International Agency for Research on Cancer’s (IARC) Group 2B classification. The Group 2B classification is based on sufficient evidence of carcinogenicity in animals but inadequate evidence of carcinogenicity in humans. Since that time, PCPC members have received multiple notices of violations from private enforcers, many of which settled, “while other enforcement actions resulted in more than one hundred (100) lawsuits in California superior courts.” Order at 5. Also since that time, there has been additional research that “has cast some doubt on IARC’s conclusion that titanium dioxide is possibly carcinogenic to humans, and there remains somewhat of a scientific debate on titanium dioxide’s (and therefore Listed Titanium Dioxide’s) carcinogenicity in humans.” Id.

PCPC filed its complaint on May 26, 2023, and its motion seeking a preliminary injunction on October 6, 2023. EHA filed its motion to intervene on September 12, 2023.

Private Enforcer Denied Right to Intervene

With regard to its motion to intervene, the District Court found that EHA has not met its burden to demonstrate that OEHHA does not adequately represent EHA’s interests, stating that it found “EHA and [OEHHA] to have identical interests in this action – upholding the constitutionality of Prop 65’s warning requirements as it relates to Listed Titanium Dioxide.” Order at 8. The District Court found that EHA failed to make a compelling showing of inadequate representation, which is a necessary element for a “motion to intervene as of right.” The District Court further found that EHA did not meet its burden for “permissive intervention,” noting that to grant intervention could delay the proceedings and there was no indication that EHA would “significantly contribute to the full development of the underlying factual issues in the suit and to the just and equitable adjudication of the legal questions presented.” Order at 11.

Preliminary Injunction against Enforcement for Lack of Prop 65 Warning

The District Court noted that injunctive relief is an “extraordinary remedy” that “preserve[s] the relative positions of the parties until a trial on the merits can be held.” Order at 12. PCPC met its burden to demonstrate that it would likely succeed on the merits, it would suffer irreparable harm in the absence of injunctive relief, and an injunction is both equitable and in the public interest.

PCPC’s likelihood of success on the merits hinges on whether it can demonstrate that the Prop 65 warning violated their First Amendment rights to be free from compelled speech. The District Court applied the standard for commercial speech set forth in Zauderer v. Office of Disciplinary Counsel, which applies to mandatory disclosure of “purely factual” and “noncontroversial” information and found that the Prop 65 warning for Listed Titanium Dioxide could be “misleading” and therefore is neither factual nor noncontroversial. In the Order, the District Court states that the Prop 65 warning was misleading to the average consumer by conveying that Listed Titanium Dioxide causes cancer in humans when IARC’s classification is based on inadequate evidence of carcinogenicity in humans. Order at 15-16. The District Court also states that a finding of irreparable harm “will almost always follow” a finding that an applicant “is likely to succeed on the merits of their constitutional claim.” Finally, the District Court found that the balance of equities and public interest favored PCPC, as it is PCPC’s First Amendment rights that are being violated.


This case, and the related cases for glyphosate and acrylamide, continues to establish precedent and guidance for First Amendment and violation of commercial speech claims in the context of Prop 65. One interesting difference between this case and the others is that OEHHA added Listed Titanium Dioxide to its Prop 65 list more than a decade ago, while the glyphosate and acrylamide cases were commenced fairly immediately after listing. Following hundreds of actions by private enforcers, PCPC pushed back, and at least for now, won.

Moreover, OEHHA seems to have taken notice, and on May 10, 2024, proposed No Significant Risk Levels (NSRL) for titanium dioxide (airborne, unbound particles of respirable size). The issuance of two NSRLs, when final, will not necessarily stop private enforcers, but it does complicate cases and assist companies that can demonstrate that exposure to titanium dioxide in their products does not exceed the relevant NSRL as established by OEHHA.