In an order filed on August 12, the US District Court for the Eastern District of California ruled that California’s Proposition 65 cancer warning requirement for certain listed forms of titanium dioxide (airborne, unbound particles of respirable size) in cosmetics and personal care products is unconstitutional under the First Amendment.
Following a preliminary injunction in 2024, the court issued a permanent injunction prohibiting enforcement of the cancer warning requirement for these products. This long-awaited development marks a significant victory for cosmetic and personal care product manufacturers and suppliers.
Background
Titanium dioxide is widely used in cosmetics as a white pigment, an opacifier, and a sunscreen active ingredient. In 2011, California listed “titanium dioxide (airborne, unbound particles of respirable size)” as a chemical “known to the State to cause cancer,” triggering Prop 65’s duty to provide a “clear and reasonable” warning before exposing consumers to the substance. The listing was added when the International Agency for Research on Cancer (IARC) classified it as “possibly carcinogenic to humans” in 2010, based on animal studies. Since the listing, many cosmetic and personal care product companies have applied Prop 65 cancer warnings to products such as loose powders, eye shadows, and sunscreen to mitigate potential enforcement risk. However, there is no conclusive scientific evidence that titanium dioxide causes cancer in humans, and debate remains.
The Court’s Reasoning
The Warning Is Not “Purely Factual”
The court’s analysis focused on whether the Prop 65 warning for titanium dioxide in cosmetics and personal care products was “purely factual and uncontroversial,” as required for compelled commercial speech under the First Amendment. The court found the warning to be misleading for several reasons.
- Implied Causation Not Supported by Science: The warning, as required by Prop 65, states that the product “can expose you to chemicals including titanium dioxide, which is known to the State of California to cause cancer.” The court found that, to an average consumer, this language strongly implies that using the product will increase their risk of cancer. However, the scientific evidence does not support a causal link between titanium dioxide exposure in cosmetics and cancer in humans. The IARC classified titanium dioxide as “possibly carcinogenic to humans” based on two rat studies, but explicitly found “inadequate evidence” of carcinogenicity in humans.
- Overall Message, Not Just Literal Truth: The court emphasized that even if each sentence of the warning is technically accurate, “the totality of the warning” is misleading to consumers. The warning elevates one side of an unresolved scientific debate and suggests a level of risk that is not supported by scientific consensus.
- Consumer Understanding: The court noted that consumers are unlikely to discern the nuanced scientific reasoning behind the listing (i.e., that the classification is based on animal studies and not on evidence of harm to humans).
The Warning Is Controversial
The court also found the warning to be “controversial,” both objectively and subjectively.
- Robust Scientific Disagreement: The court cited expert testimony and regulatory findings showing that while some agencies (like IARC) have raised concerns based on animal data, other authorities (including the US Food and Drug Administration and European regulators) have found no credible evidence of human carcinogenicity.
- Compelled Speech at Odds With Business Interests: The court recognized that requiring companies to issue a warning that they fundamentally disagree with — especially when the warning is not supported by scientific consensus — makes the compelled speech subjectively controversial for the businesses involved.
- Improper Elevation of One Side of a Scientific Debate: The court found that the warning improperly elevates a disputed scientific view, rather than reflecting a strong consensus.
First Amendment Violation
The district court concluded that compelling businesses to provide this warning was found to violate the First Amendment’s protection against compelled commercial speech. By holding that the Prop 65 warning for titanium dioxide violates the First Amendment, the court affirmed that businesses cannot be compelled to convey government-mandated warnings that are not supported by clear scientific consensus. This decision builds on recent federal appellate rulings (such as those involving glyphosate and acrylamide), and signals that courts are increasingly willing to protect commercial speech rights against controversial regulatory warnings.
Permanent Injunction
The court permanently enjoined the California Attorney General and private enforcers from filing new lawsuits to enforce the Prop 65 warning requirement for titanium dioxide in cosmetics and personal care products. However, existing Prop 65 consent decrees and settlements remain in force because the court’s order does not retroactively alter or invalidate previously finalized agreements. Companies bound by such agreements must continue to comply unless they obtain separate relief.
Implications for the Cosmetics Industry
- No New Prop 65 Lawsuits for Titanium Dioxide: Companies are no longer required to provide Prop 65 cancer warnings for titanium dioxide in cosmetics and personal care products, and new enforcement actions are barred. However, the order does not alter existing consent decrees or settlements related to Prop 65 warnings.
- Possible Reduction in Private Enforcer Actions: Since the court’s injunction not only binds the Attorney General but also private enforcers, a key feature of Prop 65 litigation, it may deter “bounty hunter” lawsuits for chemicals where the scientific basis for a warning is disputed.
- Broader Impact: The decision underscores the need for scientific consensus and factual accuracy in mandated product warnings and may influence future challenges to Prop 65 and similar regulations.
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