Coffee Anyone?: How Sound Legal Conclusions Can Break with Science under Prop 65

The Recorder

On June 15, the California Office of Environmental Health Hazard Assessment (OEHHA), which implements and administers California’s Proposition 65 program, made an unexpected pivot and proposed a new regulation clarifying that cancer warnings are not required for coffee under Proposition 65. The unusual categorical exemption could be seen as the OEHHA’s response to the media frenzy and industrywide impact caused by a recent California state court decision that required cancer warnings for coffee. The text of the proposed new rule follows below:

Section 25704. Exposures to Listed Chemicals in Coffee Posing No Significant Risk

Exposures to listed chemicals in coffee created by and inherent in the processes of roasting coffee beans or brewing coffee do not pose a significant risk of cancer.

Per an OEHHA press release, the proposed regulation is based on “extensive scientific evidence that drinking coffee has not been shown to increase the risk of cancer and may reduce the risk of some types of cancer.” The press release cites to studies by the World Health Organization’s International Agency for Research on Cancer (IARC), and concludes that “coffee is a complex mixture of numerous chemicals that includes both known carcinogens—such as acrylamide, formed during the roasting of coffee beans and brewing of coffee—and chemicals that protect against cancer, including antioxidants.”

While the proposed regulation is not yet final and is pending a public comment period that ends Aug. 30, including a public hearing on Aug. 16, parties in acrylamide litigation are already seeking court interpretation of the draft regulation.


Proposition 65 is a California-specific law that requires businesses to warn consumers about exposure to any one of the approximately 900 chemicals that the state has identified as causing cancer, birth defects, or other reproductive harm. The law provides for a “safe harbor” level for some of the listed chemicals, which is an exposure level at or below that which a business does not need to provide a warning. For chemicals listed as causing cancer, the “safe harbor” level is called a “no significant risk level” (NSRL).

Acrylamide is one of the many chemicals on the Proposition 65 list, so a warning is required for products that expose consumers to acrylamide levels above the NSRL. Acrylamide forms when certain plant-based and starchy foods are cooked and processed under certain methods at high temperatures. It also forms during the coffee roasting and brewing process, which is the basis for a state court lawsuit targeting key coffee sellers and retailers.

The Litigation

On April 13, 2010, the Council for Education and Research on Toxics (CERT) (the plaintiff) initiated a lawsuit in Los Angeles County Superior Court (Council for Education and Research on Toxics v. Starbucks, BC435759), alleging that ready-to-drink coffee products contained levels of acrylamide in violation of Proposition 65. The sweeping lawsuit named approximately 90 sellers and retailers of ready-to-drink coffee, a number of whom reached settlements earlier in the case.

The case was divided into two phases. In phase I of the case, the coffee defendants argued that the exposure level of acrylamide present in coffee did not exceed the safe harbor NSRL of 0.2 micrograms per day, such that no warning would be required. However, the court ruled that the defendants failed to meet their burden of proof for this defense.

In phase II of the case, the defendants argued that a more forgiving safe harbor, or an alternative significant risk level (ASRL), should apply. This ASRL defense allows for defendants to avoid liability by proving that exposure to the chemical does not exceed the more lenient safe harbor. The alternative level must be supported and justified by “sound considerations of public health” and must be derived by a “quantitative risk assessment” that is “based on evidence and standards of comparable scientific validity” to those used for listing the chemical on the Proposition 65 list in the first place. (See Cal. Code Regs. Title 27, § 25703(a) & (b).)

After protracted litigation, on May 7, Judge Elihu Berle of the Los Angeles County Superior Court ruled that the defendants “failed to meet their burden of proof on their alternative significant risk level affirmative defense.” As a result, the coffee products at issue would require Proposition 65 cancer warnings. In reaching his conclusion, Berle defined the scientific landscape and the parameters for the burden of proof in such cases, finding that:

  • The defendants’ expert performed the wrong type of qualitative risk assessment, focusing on acrylamide instead of acrylamide in coffee, which was necessary to quantify the risk of cancer for this case.
  • The method the defendants used to test for acrylamide was a novel scientific technique that had not been generally accepted in the scientific community, rendering it unreliable and inadmissible.
  • A second expert provided rationales for an ASRL that the court deemed to be inadequate, lacking scientific support, and not based on sound considerations of public health.
  • The defendants’ evidence that coffee confers some benefit to human health was not persuasive and was refuted by the plaintiff’s evidence.

In light of the decision, the news media widely reported that coffee requires cancer warnings and commentators questioned whether coffee causes cancer. The case is not over, however, as a third and final phase of the case on legal remedies remains pending, as well as any appeals that may be taken by the parties.

Litigants’ Response and Plaintiff’s Challenge to Proposed Regulation  

Shortly after the OEHHA proposed its new rule, the defendants filed an ex parte application asking the court to put the case on hold, as the proposed rule (if adopted) would negate the entire case. The defendants specifically asked the court to 1) vacate the hearing on the plaintiff’s motion for an injunction seeking to require nearly all defendants to provide cancer warnings, and 2) set a hearing date on their motion to stay the case. The plaintiff countered with an opposition that challenged the validity of the new regulation, stating that it is unlawful because it violates, and conflicts with, Proposition 65 itself. Specifically, the plaintiff argues that the proposed regulation creates a categorical exemption for coffee without undertaking the quantitative risk assessment that Proposition 65 requires.

The court is set to hear the defendants’ motion to stay as well as the plaintiff’s motion for an injunction on July 31.


The OEHHA’s unusual one-off intervention with respect to coffee and acrylamide reflects a larger-scale tension. For years, businesses have argued that the health impact of foods and beverages is a composite, complex scientific analysis, one that a comparatively black-and-white law such as Proposition 65 fails to appreciate. Under this phenomenon, it could be argued that the judge’s findings in the CERT case were directly attributable to the defendants’ evidence and testing methodology for establishing a safe harbor, rather than the possibility that no such safe harbor exists. In other words, the CERT decision is simply a legal, evidentiary ruling, not a substantive scientific ruling about the carcinogenicity of acrylamide coffee. The OEHHA’s proposed rule, by contrast, reflects the scientific ruling—but one that the plaintiff claims is inconsistent with the law.

With similar evidentiary, expert, and methodological obstacles that met the defendants here, how can Proposition 65 reconcile the science with the law? The effect of Proposition 65 is for the law—for example, evidentiary rulings—to dictate the conclusion. Yet sometimes, as reflected by the discord between Berle’s decision and the OEHHA’s proposed rule, even a legally sound conclusion can be inconsistent with the science.

“Coffee Anyone?: How Sound Legal Conclusions Can Break with Science under Prop 65,” by Cheryl S. Chang and Erika R. Schulz was published in The Recorder on July 17, 2018. To read this article online, please click here.

Reprinted with permission from the July 17, 2018, edition of The Recorder © 2018 ALM Media Properties, LLC. All rights reserved. Further duplication without permission is prohibited. For information, contact or visit