A federal court ruling issued in August 2025 in a case brought by the Personal Care Products Council (PCPC) is reshaping how cosmetics and personal care companies are approaching California Proposition 65 compliance as they plan for 2026, particularly for products where titanium dioxide-related warning risk has impacted packaging or formulation decisions.
Court blocks new titanium dioxide Prop 65 warning lawsuits
In its order, the U.S. District Court for the Eastern District of California issued a permanent injunction covering “Listed Titanium Dioxide,” which the Court defined as “titanium dioxide that consists of airborne, unbound particles of respirable size” when used in cosmetics and personal care products.
The Court barred California officials and private enforcers from “filing or prosecuting new lawsuits to enforce Prop 65’s warning requirement…for cancer as applied to Listed Titanium Dioxide.”
The Court also issued a declaratory ruling on the warning requirement itself, “that Prop 65’s warning as applied to Listed Titanium Dioxide is unconstitutional and violative of the First Amendment of the United States Constitution.”
The order clarified that it does not affect existing settlements or consent decrees already in place.
For companies selling products into California, the decision removes a major compliance burden tied to a commonly used pigment in cosmetics and personal care formulations, saving industry stakeholders “operating in California from expensive relabeling and reformulation, and removing the risk of lawsuits from private enforcers over alleged exposures,” Sadaf A. Nejat, a partner with Walsworth in California, told CosmeticsDesign.
Why the Court rejected the warning requirement
At the center of the case was whether California could require companies to display a cancer warning when the scientific evidence remains debated.
In its analysis, the Court focused on how consumers would interpret the warning. “Even though each sentence on its own may be factually true,” the Court wrote, “the totality of the warning is nonetheless misleading.”
The Court therefore opined the warning could likely lead consumers to believe that using cosmetics or personal care products containing titanium dioxide increases their cancer risk, even though the scientific record does not clearly support that conclusion for humans.
Titanium dioxide use and scientific context
The Court’s order outlined titanium dioxide’s long history in consumer products. “Since the 1930s Titanium dioxide has been used as a whitening pigment in the United States and most other countries around the world,” the Court wrote, noting its use in products such as toothpaste, sunscreen and makeup.
The Court also referenced federal regulations governing cosmetics, stating that titanium dioxide may be used safely in cosmetics when manufactured according to good manufacturing practices.
As detailed in the order, California added a specific form of titanium dioxide to the Prop 65 list based on an international classification that found limited evidence of cancer risk in humans but sufficient evidence in experimental animals. The Court noted that scientific debate has continued since that classification.
What the ruling could signal for future Prop 65 disputes
Although the case is limited to titanium dioxide, Nejat said the reasoning behind the decision could have broader implications.
“This ruling could certainly influence Prop 65 enforcement or labeling requirements for other ingredients in the future by underscoring that disputed or inconclusive science is insufficient to justify a warning requirement,” she said, adding that it could “even prompt closer scrutiny before new chemicals are added to the Prop 65 list.”
She said the case highlights the tension companies face when warnings are required despite ongoing scientific debate. “Reliance on limited, evolving, or disputed scientific evidence can force businesses to provide warnings that may not reflect clear or widely accepted science,” Nejat said.
That dynamic, she added, raises concerns about excessive warnings. “Perhaps the most significant issue implicated by this is the risk of overwarning and the judiciary’s longstanding effort to balance protecting consumers with preventing an unnecessary proliferation of warnings that could ultimately weaken their impact,” Nejat said.
How companies are adjusting risk management for 2026
Despite the titanium dioxide ruling, Nejat emphasized that Prop 65 remains an active compliance issue for cosmetics and personal care companies.
“Companies should continue to follow best practices to mitigate Prop 65 litigation risks,” she said, noting that manufacturers should monitor regulatory and litigation developments closely as courts apply closer scrutiny to warning requirements.
She pointed to practical steps companies should continue to take. “Best practices to mitigate Prop 65 litigation risks include product assessment, clear communication within the supply chain, and providing compliant warnings if a listed chemical is present above safe harbor levels,” Nejat said.
