In June, a federal district court ruled that California’s Proposition 65 cancer warning requirement for glyphosate violates the First Amendment rights of Monsanto and other plaintiffs and forbade the state from enforcing the warning mandate via a permanent injunction. (National Ass’n of Wheat Growers et al. v. Becerra [PDF])

The Safe Drinking Water and Toxic Enforcement Act of 1986, popularly known as “Proposition 65” or “Prop 65”, is a California law requiring publication of a list of substances (the “Prop 65 list”) known to the state to cause cancer or to be a reproductive toxicant. A substance’s being listed is determined by the scientific opinion of, among others, the EPA, the FDA, and the International Agency for Research on Cancer (IARC). The law prohibits businesses from knowingly exposing individuals to substances on the list without providing a “clear and reasonable warning”. Glyphosate was added to the Prop 65 list as a chemical known to cause cancer in July, 2017.

Noncompliance with Prop 65 can be expensive, resulting in penalties up to $2,500 per day for each failure to provide an adequate warning. Enforcement actions can be brought by the California Attorney General, as well as other state and local legal officials, like District Attorneys. The law also has what is known as a “bounty hunter” provision, allowing any person (whether they’ve suffered any harm or not) to bring a private enforcement action and recover 25% of the penalty, as well as attorneys’ fees and costs.

Before we return to the case, a brief SBM refresher on glyphosate. Glyphosate is an herbicide widely used to control weeds in various settings and is an active ingredient in Monsanto’s Roundup. In a 2014 SBM post, Steve Novella described glyphosate as “The New Bogeyman“, targeted by anti-GMO activists. As he explained, due to the introduction of Roundup-resistant GMO crops, its use has increased significantly in the last 20 years, hence its identification with GMOs. In this particular post, Dr. Novella deconstructs the claim that glyphosate causes autism and that “Half of All Children Will Be Autistic by 2025”, demonstrating how the “evidence” behind this claim confuses correlation with causation. In a more recent display of bogeyman hunting, anti-vaccine crank Robert F. Kennedy, Jr., claimed that vaccines and glyphosate are behind the current obesity epidemic, a ludicrous assertion David Gorski nicely eviscerated in a post earlier this year.

In 2018 and 2019, Dr. Novella again reviewed the scientific evidence, this time in the context of a lawsuit alleging that an agricultural worker’s lymphoma was caused by exposure to Roundup, resulting in a $289 million judgment against Monsanto, upheld on appeal.

At present from all existing evidence I think the best conclusion is that there may be a small correlation between the highest levels of agricultural exposure of glyphosate and some types of lymphoma, but the existing evidence is not of sufficient quality and consistency for a final determination. It does warrant further study, but also indicates that any potential risk is likely small. In the meantime it certainly makes sense for agricultural workers who deal with pesticides of any type to practice good safety – using protection suits and breathing masks, for example.

In adding glyphosate to the Prop 65 list, California itself did a bit of evidence cherry-picking. In 2015, the IARC classified glyphosate as “probably carcinogenic” to humans based on “sufficient evidence” that it caused cancer in experimental animals and “limited evidence” that it could cause cancer in humans. However, as the court pointed out in its decision, several other organizations, including the EPA, other agencies within the World Health Organization, and government regulators from multiple countries, have concluded that there is insufficient or no evidence that glyphosate causes cancer. The EPA reaffirmed its determination in April, 2019, and again in August 2019, stating that it would not approve herbicide labels with a Prop 65 warning, as such labels would be false and misleading and “misbranded” under the federal herbicide labeling law.

Nevertheless, as a result of the IARC’s classification of glyphosate as probably carcinogenic, it was added to the Prop 65 list, triggering the attendant warning requirement, to take effect in July, 2018.

In November, 2017, Monsanto and several farming associations, including the National Association of Wheat Growers and the National Association of Corn Growers, sued the State of California alleging that the listing of glyphosate under Prop 65 as a carcinogen, and the resulting warning requirements, violated their First Amendment rights by forcing them to make “false, misleading, and highly controversial statements”.

After earlier entering a preliminary injunction precluding California’s enforcement of the warning requirement, the court considered whether a permanent injunction was warranted.

California argued that the suit was not “ripe” for a decision because, due to certain “safe harbor” provisions in the Prop 65 law, enforcement action was unlikely. That argument was rejected by the court based, in part, on the “bounty hunter” feature of the law which, in the words of the California Court of Appeals, made institution of Prop 65 litigation “easy — and almost absurdly easy at the pleading stage and pretrial stages”.

The court then turned to the question of whether requiring Monsanto and the other plaintiffs to warn the public of glyphosate’s presumed carcinogenicity violated their First Amendment rights against “compelled speech”. As explained by one constitutional scholar, the government may no more compel one to speak (in this case, in the form of a public warning) than it can punish one for speaking.

Speech compulsions, the [U.S. Supreme] Court has often held, are as constitutionally suspect as are speech restrictions: “[T]he First Amendment guarantees ‘freedom of speech,’ a term necessarily comprising the decision of both what to say and what not to say.” [Citations omitted.]

However, the Supreme Court has held that the government can require disclosure of “purely factual and uncontroversial information” about commercial goods and services (e.g., requiring sellers to indicate where their products come from; requiring lawyers to disclose information about fees). That caselaw does not apply here, the court decided, in light of the inconsistency between the IRAC’s determination and that of others, such as the EPA, meaning that the Prop 65 warning about glyphosate was neither factual nor uncontroversial.

Thus, the Prop 65 warning would have to withstand a stricter test to pass muster under the First Amendment. As summarized by attorneys writing for the FDA Law Blog, under this standard, California

may restrict commercial speech when the restriction directly advances an important governmental interest and the restriction may not be more extensive than necessary to serve that governmental interest. The Court determined that the Prop 65 warning for glyphosate is misleading because it requires a warning that the chemical is known to the state of California to cause cancer when that statement is not true – only one organization concluded glyphosate was “probably carcinogenic” (IARC), and a multitude of other organizations that reviewed the safety of the product found the opposite. Requiring a misleading statement does not directly advance the interest of the state in informing consumers regarding potential cancer hazards. Thus, the warning could not be justified as a valid restriction on commercial speech and, therefore, is contrary to the First Amendment of the Constitution.

As of this writing, no Notice of Appeal appears on the U.S. District Court for the Eastern District of California’s online docket and the 30-day time for appeal has passed, indicating that California will not appeal the decision.

As the FDA Law Blog points out, the glyphosate decision may affect ongoing litigation involving the Prop 65 warning for acrylamide, “a popular target for bounty hunters”, which is under a similar First Amendment challenge.

Acrylamide is the result of a chemical reaction (known as the Maillard reaction) which takes place in certain types of starchy foods when they are cooked at high temperatures or otherwise processed using heat. The Maillard reaction contributes to taste, aroma and color. It occurs in a multitude of foods such as French fries, breakfast cereals, baked goods and roasted coffee.

The plaintiffs, including the California Chamber of Commerce, claim the Prop 65 warning, based on the IARC and the EPA’s determination of carcinogenicity, requires producers and sellers of foods containing acrylamide to make false, misleading, and controversial statements about their products and to mislead consumers, who will avoid their products based on incorrect information. This is because, they say, the IARC and EPA relied on studies of lab animals fed or injected with virtually pure acrylamide and, in fact, there is no evidence that acrylamide is a human carcinogen. The district court has yet to rule on that claim.

The glyphosate and acrylamide cases are two recent examples of litigation resolving clashes between government-compelled or, in some cases, prohibited speech and science. These cases have dealt with, among other subjects, a Florida ban on physicians discussing gun safety issues with parents, San Francisco’s sugar-sweetened beverage warning law, a prohibition against co-called “sexual orientation conversion therapy”, and physicians’ forced display of ultrasounds and recitation of government-scripted information to patients seeking abortions. No doubt they won’t be the last.


  • Jann J. Bellamy is a Florida attorney and lives in Tallahassee. She is one of the founders and Board members of the Society for Science-Based Medicine (SfSBM) dedicated to providing accurate information about CAM and advocating for state and federal laws that incorporate a science-based standard for all health care practitioners. She tracks state and federal bills that would allow pseudoscience in health care for the SfSBM website.  Her posts are archived here.    

Posted by Jann Bellamy

Jann J. Bellamy is a Florida attorney and lives in Tallahassee. She is one of the founders and Board members of the Society for Science-Based Medicine (SfSBM) dedicated to providing accurate information about CAM and advocating for state and federal laws that incorporate a science-based standard for all health care practitioners. She tracks state and federal bills that would allow pseudoscience in health care for the SfSBM website.  Her posts are archived here.