Seattle Statement on Glyphosate and Public Health

This statement was finalized and adopted at the Seattle Glyphosate Symposium, which took place 25-26 March, 2026 in Seattle, Washington. The statement’s authors are listed below.

Glyphosate, a broad-spectrum herbicide (plant killer) typically marketed as Roundup, is the world’s most widely used pesticide. The diversity and magnitude of glyphosate uses in agriculture, in forestry and in industrial, commercial, residential and municipal settings have grown dramatically since first approval in 1974. 

Humans are exposed to glyphosate through direct spraying and other skin contact, through occupational or residential proximity to sprayed areas, through exposure to dust and through consumption of food and water contaminated with glyphosate residues. Food is the main route of exposure for most people while occupational exposures are typically the highest.

National and international biomonitoring surveys detect glyphosate in samples collected from 70-80% of all people examined, including children.

Glyphosate and glyphosate-based herbicides (GBHs) harm human health and can cause cancer. The comprehensive evidence supports this conclusion, with the strongest epidemiological evidence linking exposure to increased risk of non-Hodgkin lymphoma, a cancer of the lymphatic system.

There is additional evidence from human and/or animal studies that glyphosate and GBHs increase the risk of multiple adverse health effects in addition to cancer, including diseases of the kidney and liver, and impacts to the reproductive, endocrine, neurological, and other metabolic systems. Children, infants and fetuses are the most susceptible. 

Further strong evidence finds that glyphosate and GBHs cause genetic damage, oxidative stress, and hormonal disruption — biological changes that can set disease in motion. Our understanding of glyphosate’s ability to cause these changes has developed from multiple lines of evidence in animal, human and in vitro studies.

Additional research is needed to better understand the full extent of glyphosate’s and GBH’s effects on human health and the underlying mechanisms involved, such as epigenetic alterations, microbiome disruption and endocrine effects. 

The evidence that glyphosate and GBHs harm human health at levels of current use is now so strong that no additional delays in regulation of glyphosate can be justified. Regulatory agencies in countries around the world should treat glyphosate and GBHs as hazardous, as some countries have started to do. Agencies should act without further delay to limit their use, or eliminate them if legally required, to protect public health. 

Preventive measures to reduce human exposures while handling and applying glyphosate are accessible, proven effective, and inexpensive. These actions should be implemented without delay while research continues.

Safeguards must be implemented to ensure that any reduction in glyphosate use does not result in regrettable increases in the use of other equally or more harmful pesticides, for example paraquat. 

Glyphosate is not the only pesticide that has been inadequately evaluated or regulated. The approval processes globally for all existing and new pesticides are weak and fail to protect human health, especially the health of infants and children. This system needs to be fundamentally revised. Regulatory agencies need to make pesticide approval decisions based on a more comprehensive and unbiased suite of health effects data. If pesticide use is approved, these agencies must closely monitor use, exposure data and harmful outcomes, especially for susceptible and highly exposed groups. The costs of obtaining such data must be borne by the pesticide industry, but the testing must be conducted by laboratories and organizations independent of the pesticide industry and free from financial conflicts of interest (COI), defined as funding from industries and trade associations that have a financial stake in the outcome.

Risk-assessment methods and processes used to evaluate pesticides must be updated to use best-available science, including: using transparent, consistent and unbiased approaches to evaluate all the evidence; accounting for human variability and susceptible populations such as fetuses, infants and children, and highly exposed populations such as farmworkers; accounting for cumulative exposures and risks for pesticides that contribute to common adverse health outcomes; and identifying adverse health effects and risks at all exposure levels. This is clearly not the case now.

All scientific evidence used in pesticide evaluations must be publicly available, not labeled proprietary or restricted to active ingredients, and must comply with laws protecting human subjects in research. Financial COI, which do not include government funding, must be addressed throughout the research and regulatory processes, including accounting for bias from industry-funded studies, and ensuring that individuals with financial COI are barred from participating in scientific advisory panels and other bodies that formally review scientific data.

Ultimately, pesticide use must be reduced overall, and eliminated to the extent possible. This is consistent with the United Nations Global Biodiversity Framework global target to reduce pesticide risks by 50% by 2030 relative to 2010–2020 and replace pesticides with safer, more sustainable pest control systems that rely more on prevention than treatment. This is imperative for the health of humans, ecosystems and future generations.

Signed by (Affiliations noted for identification purposes only)