Consider calling your House member and implore them to vote against the liability shield in the Farm Bill. This means voting against the entire bill as it is too late for amendments. Don’t let them try to sweet talk you about how this is not a liability shiled—it is a de factor shield because it restricts label changes, slows EPA reviews of existing products, and give the EPA administrator the ability to exempt selected substances from review. Not to mention restricting judges from considering any information beyond the label in liability cases. It is a very bad bill!
The most definitive recent study on glyphosate is the Global Glyphosate Study (GGS), conducted by the Ramazzini Institute in Italy. While the institute released preliminary findings in late 2023, the full peer-reviewed carcinogenicity results were published in the journal Environmental Health on June 10, 2025.
The study is considered the most comprehensive long-term toxicological investigation into glyphosate and its commercial formulations:
Glyphosate-based herbicides (GBHs) are the world’s most widely used weed control agents. Public health concerns have increased since the International Agency for Research on Cancer (IARC) classified glyphosate as a probable human carcinogen in 2015. To further investigate the health effects of glyphosate and GBHs, the Ramazzini Institute launched the Global Glyphosate Study (GGS), which is designed to test a wide range of toxicological outcomes. Reported here are the results of the carcinogenicity arm of the GGS.
Methods
Glyphosate and two GBHs, Roundup Bioflow used in the European Union (EU) and RangerPro used in the U.S., were administered to male and female Sprague–Dawley (SD) rats, beginning at gestational day 6 (via maternal exposure) through 104 weeks of age. Glyphosate was administered through drinking water at three doses: the EU acceptable daily intake (ADI) of 0.5 mg/kg body weight/day, 5 mg/kg body weight/day and the EU no-observed adverse effect level (NOAEL) of 50 mg/kg body weight/day. The two GBH formulations were administered at the same glyphosate-equivalent doses.
Results
In all 3 treatment groups, statistically significant dose-related increased trends or increased incidences of benign and malignant tumors at multiple anatomic sites were observed compared to historical and concurrent controls. These tumors arose in haemolymphoreticular tissues (leukemia), skin, liver, thyroid, nervous system, ovary, mammary gland, adrenal glands, kidney, urinary bladder, bone, endocrine pancreas, uterus and spleen (hemangiosarcoma). Increased incidences occurred in both sexes. Most of these involved tumors that are rare in SD rats (background incidence < 1%) with 40% of leukemias deaths in the treated groups occurring before 52 weeks of age and increased early deaths were also observed for other solid tumors.
Conclusions
Glyphosate and GBHs at exposure levels corresponding to the EU ADI and the EU NOAEL caused dose-related increases in incidence of multiple benign and malignant tumors in SD rats of both sexes. Early-life onset and mortality were observed for multiple tumors. These results provide robust evidence supporting IARC’s conclusion that there is “sufficient evidence of carcinogenicity [of glyphosate] in experimental animals”. Furthermore, our data are consistent with epidemiological evidence on the carcinogenicity of glyphosate and GBHs.
Key Findings of the 2025 Ramazzini Study
The researchers (Panzacchi et al.) conducted a 26-month study on Sprague-Dawley rats, exposing them to glyphosate and two commercial products (Roundup BioFlow and RangerPro) via drinking water.
Early-Onset Leukemia: The most striking finding was a statistically significant increase in leukemia cases in rats, with roughly half of these deaths occurring before the age of one (equivalent to young adulthood in humans).
Low-Dose Toxicity: The study observed these effects even at the Acceptable Daily Intake (ADI) of 0.5 mg/kg body weight per day—a level currently considered safe by European and U.S. regulatory agencies.
Multiple Tumor Sites: Beyond leukemia, the study reported increased incidences of tumors in the skin, liver, thyroid, bone, and nervous system.
Formulation vs. Pure Glyphosate: The researchers noted that while pure glyphosate was carcinogenic, the commercial formulations (which include “inert” surfactants) appeared to enhance the toxic effects, particularly for leukemia.
Scientific Controversy and Pushback
The results have sparked intense debate among toxicologists and regulatory bodies:
Criticism of Control Groups: Organizations like the German Federal Institute for Risk Assessment (BfR) and industry-aligned groups (e.g., Genetic Literacy Project) have criticized the study. They argue that the control group (which had zero leukemia cases) was an anomaly, as Sprague-Dawley rats often develop “spontaneous” tumors as they age.
Methodological Debates: Critics claim the statistical analysis used by the Ramazzini Institute overemphasized rare tumors and that the survival rates of the rats fell below standard OECD guidelines for such studies.
Director Ousted: In a dramatic development in January 2026, the director of the Ramazzini Institute’s cancer research center, Daniele Mandrioli, was reportedly ousted following a “reorganization.” This has led to public outcries and allegations of industry pressure to suppress the study’s findings.
It is, however, very commendable that the Ramazzini Institute had the courage to carry out the Global Glyphosate Study (GGS). After all, it is simply beyond belief that big industry has managed to ensure its impunity in so many areas.
It is, however, very commendable that the Ramazzini Institute had the courage to carry out the Global Glyphosate Study (GGS). After all, it is simply beyond belief that big industry has managed to ensure its impunity in so many areas.
Dr. Nass, thank you for this informationn about the terrible Farm Bill.
I just emailed my representative and urged him to vote against it.
By the way, do xou ever sleep? Just asking, because you posted this substack article at 3:19 am!