Last Monday, a federal judge temporarily barred California from requiring cancer warnings on products that contain detectable amounts of glyphosate—the main ingredient in Monsanto’s flagship herbicide Roundup.[1] Trace residues of glyphosate in food products had already become a potential target of Proposition 65 bounty hunters, who presumably had already begun testing foods purchased in California grocery stores to determine which companies would receive their first round of 60-day intent to sue notices.

The preliminary injunction by U.S. District Court Judge William B. Shubb declined to remove glyphosate on the Proposition 65 list of chemicals “known to the State of California to cause cancer,” but, at least for now, bars the State from imposing the corresponding warning requirement while the case challenging its listing proceeds on its merits. The court’s ruling is based on a First Amendment, compelled false speech analysis—Judge Shubb determined that a Prop 65 cancer warning on glyphosate or glyphosate residues could mislead a reasonable consumer since the vast majority of scientific and health organizations have found no evidence that glyphosate causes cancer in humans.

The preliminary injunction is a win for glyphosate manufacturers, agriculture, and food companies as trace amounts of glyphosate—one of the most widely used herbicides in agriculture—can remain on crops after they are harvested. Residues of it can be detected in a variety of produce, processed commodities, and finished food products. Indeed, testing by the U.S. Food and Drug Administration and environmental groups have detected trace amounts of glyphosate in an assortment of agricultural commodities and food products, including in soybeans, corn, oats, and baby food to name just a few.

Background of Glyphosate Listing

In July of 2017, glyphosate was added to the Proposition 65 list of chemicals due to the conclusion by the International Agency for Research on Cancer (IARC) that the herbicide glyphosate is “probably carcinogenic” to humans. IARC’s conclusion is controversial as IARC is the only national or international agency to have declared the substance a probable carcinogen despite recent review of glyphosate by a number of other respected scientific and health organizations including the U.S. Environmental Protection Agency.

Under California’s unique Proposition 65 law, however, a chemical can be listed as “known to cause cancer” due to an “authoritative body’s” designation of a chemical as a carcinogen based on animal studies that involve unrealistic doses and that involve only one pathway of exposure. IARC has long been designated by California as one such authoritative body and, here, its listing of glyphosate was based on a study conducted only on its inhalation by laboratory mice. No studies exist demonstrating that the chemical causes cancer in humans or that it causes cancer in laboratory animals by means of ingestion.

However, under Proposition 65, the California Office of Environmental Health Hazard Assessment (OEHHA) determined that IARC’s finding compelled it to list glyphosate as known to the State to cause cancer for all purposes and regardless of threshold dose or route of exposure. Under Prop 65 therefore, warnings are presumptively required on anything sold in California’s vast marketplace beginning only a year after the date of the listing, so the court’s preliminary injunction will have the effect of delaying enforcement of the warning requirement on glyphosate beyond July 1st of this year.

Issuance of the Preliminary Injunction

In his decision last week, Judge Shubb concluded that, to the extent its listing under Proposition 65 necessitates warnings for glyphosate, California is compelling commercial speech. Under the scrutiny such government-induced speech demands under the First Amendment of the U.S. Constitution, he found that the warnings for glyphosate need to be based on “purely factual and uncontroversial information,” as determined by the U.S. Supreme Court’s ruling in Zauderer v. Office of Disciplinary Counsel of Supreme Court. Judge Schubb then reasoned that a conclusion that glyphosate causes cancer is hardly uncontroverted given the disparity between IARC and other scientific and health authorities. He further found that, given the controversy, a Prop 65 warning for it would suggest a finding of it causing cancer in humans, which would be misleading to the average consumer. He then determined that the balancing of interests involved weighed in favor of restraining the enforcement of the warning requirement for glyphosate while the remainder of the case was decided.

Importance of the Court’s Ruling

This issue of whether Prop 65 warnings will ultimately be required for glyphosate and its residues in food products is far from being decided with finality. The preliminary injunction may be appealed by the State and OEHHA is likely to promulgate a generous no significant risk level for glyphosate later this year that may effectively moot the need for warnings on glyphosate in food residues.

However, regardless of how the battle on glyphosate warnings ultimately plays out, Judge Schubb’s decision and reasoning may still prove to be an important and favorable legal development for companies impacted by California’s Proposition 65. In particular, his reliance on the First Amendment and characterization of the Prop 65 warning requirement as compelled speech that cannot be false and misleading may have implications on the legality of requiring warnings about a number of other Proposition 65-listed chemicals and form the basis of a defense in other cases. In fact, Morrison & Foerster attorneys have previously raised First Amendment arguments like the one on which Judge Shubb based his ruling in previous Proposition 65 cases, but they have successfully been defended on other grounds before the courts involved reached the Constitutional question presented.