Prop 65 Warning for Titanium Dioxide Struck Down

California’s Proposition 65 warning requirement for respirable titanium dioxide violates the First Amendment, the District Court for the Eastern District of California ruled on August 12, 2025, in The Personal Care Products Council v. Bonta, No. 2:23-cv-01006.

The decision is the latest in a series of rulings invalidating Prop 65 warnings for chemicals with disputed health risks. In 2023, the Ninth Circuit struck down a warning requirement for glyphosate, and in early 2025, the Eastern District of California invalidated a warning requirement for dietary acrylamide.  Blog posts on those cases can be found here and here.

The titanium dioxide order follows the same analytical framework. First, the court held that the warning failed the test set forth in Zauderer v. Office of Disc. Counsel, 471 U.S. 626 (1985), which allows for compelled commercial disclosures when they are “purely factual and uncontroversial.”

“[T]he parties admit that there is a clear debate over whether Listed Titanium Dioxide cases cancer in humans,” the order states.  “The Court finds the Prop 65 warning would likely improperly elevate ‘one side of a legitimately unresolved scientific debate.’”

As in the glyphosate and acrylamide cases, the court focused on how an average consumer would perceive the warning, not just whether each sentence was literally accurate.  “Even though each sentence on its own may be factually true, ‘the totality of the warning’ is nonetheless misleading,” the order states.

Second, the court found that the warning failed intermediate scrutiny under Central Hudson Gas & Electric Corp. v. Public Service Commission of New York, 447 U.S. 557 (1980) and was therefore unconstitutional.  The court concluded that the warning does not advance California’s interest in public health because titanium dioxide’s risks are not confirmed, and the state has less burdensome alternatives—such as making information available online.

Titanium dioxide is commonly used as a whitening pigment in cosmetic and personal care products. Its Prop 65 listing applies only to “airborne, unbound particles of respirable size.”