California Appeals Court Upholds State’s Reliance On Conclusion By A Foreign Agency To Classify Glyphosate As “Cancer-Causing”

Two courts recently examined California’s regulation of glyphosate, a widely used pesticide ingredient, for its alleged health risks via the state’s Proposition 65 warning program. The decisions are noteworthy for the contrasting approaches that they take with respect to the amount of deference to give to international regulatory actions that are incorporated by reference into U.S. law.

On April 19, 2018, a California appellate court rejected a challenge by Monsanto and several industry groups that glyphosate was improperly listed under California’s Proposition 65. At issue in this appeal was the state’s 2017 classification of glyphosate as a “cancer-causing” substance. Consistent with state law, this classification by the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) was automatically triggered when the International Agency for Research on Cancer (IARC), a France-based agency of the World Health Organization determined in 2015 that glyphosate is “probably carcinogenic to humans.” IARC’s conclusion was based on a public literature review conducted by 17 IARC-selected scientists, and contradicted numerous prior evaluations by OEHHA and a wide range of U.S., foreign, and international regulatory bodies finding no connection between glyphosate and cancer. Despite the contradicting conclusions from those other bodies, the California court nevertheless concluded that the statutory delegation of authority to IARC under Prop 65 was consistent with California law, and that the basic statutory structure, together with IARC’s own reputation and motivation, are sufficient to protect the statute from a facial constitutional challenge based on its delegation of decision-making authority to IARC.

This same listing decision was also at issue in a federal court decision in February 2018. There, the court did not invalidate the listing of glyphosate, but has nevertheless preliminarily prohibited the state from enforcing warning requirements based on the listing while the case remains under consideration. Unlike the California court, the federal court found that, whatever the threshold for listing in California, a “cancer-causing” warning under Proposition 65 would be “inherently misleading” in light of the conflicting findings by other regulatory authorities.

This pair of glyphosate cases exemplifies the regulatory uncertainty that arises when the complex scientific findings behind laws and regulations are challenged in courts. Proposition 65’s listing mechanism, and similar state regulatory programs that incorporate findings by foreign entities, are likely to face continued scrutiny as their impacts expand, particularly when the findings rely on decisions or judgments made by non-U.S. institutions. The tension between these decisions by state and federal courts in California illustrates the challenges that arise when regulatory agencies base their decisions on controversial scientific judgments about human health or environmental issues, particularly when those judgments are made by foreign entities. 

The State Court Listing Challenge (Monsanto v. OEHHA)

As required by Proposition 65, California maintains lists of chemicals known to the state to cause cancer or reproductive harm.1 Among other listing procedures, a chemical must be added to the Proposition 65 list if it is classified by IARC as “probably carcinogenic to humans” with sufficient evidence from experimental animals. Twelve months after California lists a chemical, businesses responsible for exposing people in California to the chemical must provide a “clear and reasonable” warning of its cancer-causing status.

Following IARC’s classification of glyphosate in 2015, industry groups sued OEHHA in state court on various state and federal constitutional bases to stop the listing of glyphosate under Proposition 65. The groups subsequently appealed the trial court’s dismissal of their claims, arguing that the Proposition 65 listing mechanism unconstitutionally cedes regulatory authority to IARC, which Monsanto described as an “unelected, undemocratic, unaccountable, and foreign body.”    

In affirming the lower court’s decision, the appellate court held that IARC was not a “private corporation,” focusing on IARC’s “formation as an intergovernmental agency under international law and its oversight and general management by United States and foreign government agents.”2 The court also held that the listing mechanism did not unlawfully delegate authority to IARC, reasoning that the electorate had already resolved the fundamental policy issues underlying Proposition 65. According to the court, the various listing procedures contained in Proposition 65 merely represent “the working details on how to implement the broader policy of notification and warning with respect to carcinogenic compounds.”3 

Significantly, the court also determined that Proposition 65 incorporates adequate directions and safeguards with respect to its listing procedures. Specifically, the court highlighted IARC’s status as “an international agency created specifically to scientifically investigate potentially carcinogenic compounds,” and whose reputation, authority, and funding all depend on its work “being accepted as scientifically sound.” From the court’s perspective, IARC is therefore “motivated to avoid arbitrarily defining compounds as carcinogenic.”4 

The Federal Court First Amendment Challenge (National Association of Wheat Growers v. Zeise)

The California Court of Appeal’s decision came just weeks after -- and stands in contrast to -- a Federal court’s decision to grant an industry group’s motion to preliminarily enjoin California from enforcing the glyphosate warning requirement in a separate case brought by Monsanto and a number of industry and trade associations.5 

In that case, plaintiffs sued OEHHA in federal court, claiming that the listing of, and the enforcement of warning rules against, glyphosate under Proposition 65 violate the First Amendment of the U.S. Constitution. Specifically, plaintiffs claimed that both the listing and the warning requirement are compelled commercial speech. Plaintiffs moved for a preliminary injunction against both the listing and enforcement of warning requirements with respect to glyphosate.

The court denied the motion with respect to the listing of glyphosate.6 It reasoned that the listing itself, conducted by the state of California, is government speech, not private speech. Thus, the listing action was outside the protection of the Free Speech Clause of the First Amendment. 7 In addition, the court found that the listing would not likely harm the plaintiffs by itself – only the warning requirements imposed obligations on the plaintiffs. Considering these two points, the court found that the plaintiffs failed to show that the listing likely violated the First Amendment.8

But the court preliminarily enjoined the enforcement of warning requirements for glyphosate. The court explained that the Proposition 65 warning, as a mandated disclosure by commercial speakers about their products or services, represents commercial speech subject to protection by the First Amendment.9  

The court focused its analysis on whether the compelled warning was purely factual and uncontroversial. Factual disclosures can be literally true, but one-sided or incomplete, and thus misleading or controversial.10 The court concluded that the required warning would be misleading to the ordinary customer.  

Unlike Monsanto v. OEHHA, the court in this case focused on the fact that, to date, only IARC had concluded that glyphosate was a probable carcinogen, while other organizations, including EPA, EU health agencies, and even other WHO agencies, had found no evidence that it caused cancer. “A reasonable consumer would not understand that a substance is ‘known to cause cancer’ where only one health organization had found that the substance in question causes cancer and virtually all other government agencies and health organizations that have reviewed studies on the chemical had found there was no evidence that it caused cancer. Under these facts, the message that glyphosate is known to cause cancer is misleading at best.”11 

The court held that, in light of the positions taken by these other agencies, it would not be “factually accurate and uncontroversial” to convey the message that glyphosate was undisputedly carcinogenic. In fact, the court added that “[i]t is inherently misleading for a warning to state that a chemical is known to the state of California to cause cancer based on the finding of one organization … when apparently all other regulatory and governmental bodies have found the opposite, including the EPA[.]”12


Although both the state and federal courts rejected challenges to California’s underlying decision to list glyphosate as a cancer-causing substance, the federal court’s injunction against the Proposition 65 warning requirement was based on an evaluation of the wider scientific consensus around glyphosate that the state court expressly declined to consider. According to the state Court of Appeal, Proposition 65 is designed to cast a wide net for listing products, even if potential conflicts exist among various authorities. In dismissing Monsanto’s concerns about California’s delegation of the listing decision to an unaccountable foreign body, the state court’s opinion indicates that IARC’s international prominence effectively deters it from engaging in unsound or arbitrary science. By contrast, the federal court’s injunction suggests that California’s reliance on the conclusion of a single foreign organization -- no matter its reputation -- may be improper when the clear weight of scientific opinion is otherwise opposed.   

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Beveridge & Diamond’s reputation for excellence in pesticide law is based on forty years of working with U.S. and international clients who research, develop, obtain government approvals for, manufacture, promote, and use conventional pesticides and pesticides produced through biotechnology.  We represent both large and small companies, as well as task forces of companies, with an emphasis on entities that invest in research to discover, develop, and defend new technology.  We work with each client to identify its business objectives, and then to establish and implement the most effective regulatory, commercial, litigation, and legislative strategies to achieve or exceed those objectives. Please contact Kathy Szmuszkovicz, Alan Sachs, or any member of our Pesticides practice group.

Beveridge & Diamond’s Consumer Products Practice advises clients in California and worldwide on Proposition 65 issues, as well as a wide range of other product-related environmental issues. For more information about OEHHA’s Proposition 65 Clear and Reasonable Warning requirements, Proposition 65 litigation, and how Proposition 65 relates to your business, please contact Gary J. Smith, Lauren Hopkins, or Mark Duvall.

1 27 Cal. Code Reg. § 27001.

2 Opinion, Monsanto Co., v. Office Envtl. Health Hazard Assessment, F075362 (Cal. Ct. App. 5th Dist. Apr. 19, 2018), at 15.

3 Id. at 19.

4 Id. at 28.

5 Memorandum and Order, Nat’l Ass’n of Wheat Growers v. Zeise, 2:17-cv-02401 (E.D. Cal. Feb. 26, 2018).

6 Id. at 12.

7 Id. at 11.

8 Id.

9 Id. at 12.

10 Id. at 12-13 (quoting Am. Meat Inst. v. U.S. Dep’t of Agric., 760 F.3d 18, 27 (D.C. Cir. 2014)).

11 Id. at 14.

12 Id. at 16 (emphasis added).