Roundup Lawsuit

The Science Behind Glyphosate and Cancer

The scientific case against glyphosate rests on multiple lines of evidence. First, laboratory studies have consistently shown that glyphosate causes DNA damage through oxidative stress and direct genotoxicity. Glyphosate generates reactive oxygen species that cause single-strand and double-strand DNA breaks, and studies of agricultural workers show elevated biomarkers of chromosomal damage including micronuclei and sister chromatid exchanges.

Second, animal studies have demonstrated that glyphosate exposure leads to tumor development. The IARC evaluated these studies and found "sufficient evidence" of carcinogenicity in experimental animals. Third, epidemiological studies of human populations exposed to glyphosate show elevated cancer rates. The Agricultural Health Study, a massive cohort study of over 50,000 pesticide applicators conducted by the National Cancer Institute, found increased risk of non-Hodgkin lymphoma in the highest-exposure group, although the overall association was not statistically significant across all exposure levels.

The Zhang et al. meta-analysis published in Mutation Research in 2019 pooled data from six epidemiological studies and found a statistically significant 41 percent increase in NHL risk among people with the highest cumulative glyphosate exposure. This finding was consistent across multiple study designs and populations.

What Monsanto Knew and When

Internal Monsanto documents obtained through litigation discovery paint a damning picture of corporate knowledge and concealment. As early as 1999, Monsanto commissioned geneticist Dr. James Parry to evaluate glyphosate’s genotoxicity. When Parry concluded that glyphosate was potentially genotoxic and recommended further testing, Monsanto buried his findings and hired a different scientist who produced more favorable results.

Dr. Donna Farmer, Monsanto’s lead toxicologist, wrote in internal emails that "you cannot say that Roundup is not a carcinogen" because the company had "not done the necessary testing on the formulation to make that statement." Senior toxicologist William Heydens proposed in an internal memo that Monsanto scientists ghostwrite sections of published safety reviews, writing that "we would be keeping the costs down by us doing the writing and they would just edit and sign their names." Multiple published papers defending glyphosate safety were later identified as Monsanto-authored.

Internal emails also revealed a close relationship between Monsanto and Jess Rowland, then-chair of the EPA’s Cancer Assessment Review Committee. Rowland allegedly told a Monsanto executive he would try to kill a separate Health and Human Services review of glyphosate, reportedly saying "if I can kill this, I should get a medal."

The Future of Roundup Litigation

Roundup litigation has produced billions of dollars in settlements and several jury verdicts and remains active. The U.S. Supreme Court's 2024 denial of Bayer's certiorari petition on federal-preemption grounds left that defense unavailable, and the litigation has continued.

For claimants who have not yet filed, the settlement represents both an opportunity and a deadline. The settlement structure will establish compensation tiers based on diagnosis severity, exposure history, and damages. Claimants who delay may face reduced compensation or exhaustion of settlement funds. New claims continue to be filed as more people learn about the Roundup-cancer connection and as previously undiagnosed cancers are identified.