Photo by Tingey Injury Law Firm on Unsplash
What happens when an international research agency decides that the most widely used herbicide in the world may cause cancer? Well, it depends.
Are you asking a judge? Or jurors?
According to an order issued late last month by Eastern District of California Judge William B. Shubb, a 2015 determination by the International Agency for Research on Cancer (“IARC”) that glyphosate — the primary ingredient in Monsanto’s Roundup weed killer products — is “probably carcinogenic to humans” is insufficient to justify forcing the company to label its products as “known to the state of California to cause cancer.”
Judge Shubb’s order cited contrary findings by the U.S. Environmental Protection Agency and other regulatory bodies that there is insufficient or no evidence that glyphosate causes cancer in humans. Consequently, the court concluded that the State of California cannot compel Monsanto to affix the controversial Proposition 65 warning to the company’s Roundup herbicide products.
Judge Shubb’s Prop 65 ruling, however, has been largely overshadowed by an announcement from Bayer AG (Monsanto’s parent company) — within 48 hours of the injunction — of a series of agreements resulting in a $10.1 billion payment to settle current and future litigation over the RoundUp glyphosate products.
So in the end, there is not enough evidence for California to force Monsanto to warn today’s Roundup buyers that its product is known to cause cancer — but Roundup customers who’ve already filed suit against the company may get billions in settlement money. How does the IARC classification of glyphosate as “probably carcinogenic to humans,” warrant such an enormous payout, when the same classification was given to hamburgers?
Here’s the rub: IARC explicitly does not consider how much of a substance someone might be exposed to, only whether there is any evidence that any level of exposure could conceivably cause cancer. As explained here, IARC engages in “hazard assessment,” gauging whether the substance “is capable of causing cancer under some circumstances.” This differs substantially from “risk assessment,” or “the probability that cancer will occur, taking into account the level of exposure,” which is the approach taken by the EPA and other health agencies worldwide.
The risk assessment approach reflects the toxicology maxim that “the dose makes the poison” — at sufficiently high doses, nearly everything can cause cancer. Additionally, the IARC classification scheme completely fails to distinguish between substances of extreme and questionable risk — plutonium and processed meat share the same “carcinogenic to humans” classification. The hazard assessment approach, and the accompanying classification system used by IARC, lead to results that can easily confuse consumers — as well as jurors.