Federal Court Enjoins California Prop 65 Enforcement for Diethanolamine in Cosmetics: What Comes Next?

By: Anne Marie Ellis, June 26, 2026

In a significant and closely watched development for the cosmetics and personal care industry, a federal court in the Eastern District of California has entered a final judgment and permanent injunction barring enforcement of Proposition 65 warning requirements for diethanolamine (“DEA”) in cosmetic and personal care products.

The decision—arising from The Personal Care Products Council v. Bonta—marks the latest in a growing line of First Amendment challenges to Proposition 65 warning mandates and signals continued judicial skepticism toward compelled speech where scientific consensus is disputed.

At-a-Glance Takeaways

• Enforcement halted: California’s Attorney General is permanently enjoined from bringing new Prop 65 enforcement actions related to DEA in cosmetic and personal care products.
• First Amendment holding: The court concluded that, based on the current state of the science, the cancer warning requirement cannot be constitutionally enforced.
• Industry impact: Companies may have immediate grounds to revisit DEA warning practices—but should proceed strategically.
• Not necessarily permanent: The injunction can be revisited if scientific or legal developments change.

Background: A Continuing Line of Prop 65 Challenges

DEA has been listed as a carcinogen under Proposition 65 since 2012.

In this case, The Personal Care Products Council (“PCPC”) brought a constitutional challenge under 42 U.S.C. § 1983, arguing that requiring cancer warnings for DEA exposure in cosmetics constitutes compelled speech in violation of the First Amendment.

This lawsuit builds on a series of recent federal cases—including:

• National Association of Wheat Growers v. Bonta
• California Chamber of Commerce v. Bonta
• Prior PCPC litigation involving titanium dioxide

Each of these cases reflects a trend toward heightened judicial scrutiny of Proposition 65 warnings where underlying scientific conclusions are contested. [

The Court’s Order: A Broad Injunction

On June 23, 2026, the court entered an order regarding final judgment and permanent injunction that includes two key components.

1. Prohibition on Enforcement

The Attorney General and those acting in concert with the state are permanently barred from filing or prosecuting new lawsuits to enforce Prop 65 warning requirements for DEA in cosmetics.

2. Constitutional Determination

The court further declared that the warning requirement, as applied to DEA, cannot be constitutionally enforced consistent with the First Amendment based on the current state of the science.

The reasoning aligns with recent First Amendment jurisprudence restricting compelled commercial speech that is not purely factual and uncontroversial.

Key Nuances: What the Decision Does (and Does Not) Do

1. The Injunction Is Targeted but Meaningful

The order applies specifically to:

• DEA
• Cosmetic and personal care products
• Enforcement actions brought by the Attorney General and those in privity

The result stems from a stipulated judgment reflecting the parties’ agreement in light of current science and precedent.

2. The Attorney General Retains a Path to Revisit

The injunction may be revisited if there is a change in scientific evidence or governing law under Federal Rule of Civil Procedure 60(b).

3. Private Enforcement Questions Remain

The order does not expressly resolve whether private enforcers may attempt to pursue similar claims, leaving potential litigation exposure in place.

Practical Implications for Industry

Immediate Considerations

Companies should evaluate:

• Current labeling practices involving DEA
• Whether existing claims or notices can be challenged
• Alignment across supply chain partners

Strategic Caution Is Warranted

Despite the favorable ruling, companies should avoid broad changes without analysis. Consider:

• Ongoing risk from private enforcers
• Products or uses outside the scope of the order
• Potential future changes in scientific or regulatory positions

Broader Trend Line

The decision reinforces a continuing trend toward constitutional challenges to Proposition 65 enforcement where scientific consensus is disputed.

Looking Ahead: Pressure on the Prop 65 Framework

The DEA injunction contributes to increasing pressure on the Proposition 65 framework. Developments to watch include:

1. Additional First Amendment challenges targeting other listed chemicals
2. Potential regulatory adjustments by California agencies
3. Continued migration of Prop 65 litigation into federal court

For product manufacturers and distributors, Proposition 65 compliance is increasingly intertwined with constitutional considerations, not just regulatory obligations.

Bottom Line

The PCPC v. Bonta judgment represents a meaningful limitation on Proposition 65 enforcement in its current form. It halts Attorney General enforcement for DEA warnings, reinforces the role of the First Amendment in evaluating compelled warnings, and creates new strategic considerations for companies navigating compliance.

This communication is not intended to create or constitute, nor does it create or constitute, an attorney-client or any other legal relationship. No statement in this communication constitutes legal advice nor should any communication herein be construed, relied upon, or interpreted as legal advice. This communication is for general information purposes only regarding recent legal developments of interest, and is not a substitute for legal counsel on any subject matter. No reader should act or refrain from acting on the basis of any information included herein without seeking appropriate legal advice on the particular facts and circumstances affecting that reader. For more information, visit www.buchalter.com.