Public Interest Groups on WHO's decision on Glyphosate

March 26, 2015

The Honorable Gina McCarthy
Administrator, U.S. Environmental Protection Agency
1200 Pennsylvania Ave, NW
Washington, D.C. 20460

Dear Administrator McCarthy:

We the undersigned organizations strongly urge the Environmental Protection Agency to weigh heavily the decision last week by the World Health Organization to categorize glyphosate (trade name “Roundup®”) as “probably carcinogenic to humans” (Group 2A).[1] The announcement was extremely timely inasmuch as EPA is preparing to issue its preliminary risk assessment of the widely used herbicide under the Federal Insecticide, Fungicide, and Rodenticide Act (7 U.S.C. § 136a(g)).

The World Health Organization’s research arm, the International Agency for Cancer Research (IARC), made its updated cancer determination for glyphosate following a review of the available scientific research by 17 of the world’s top oncology experts from 11 countries.

In light of the WHO’s decision, we also urge the EPA not to register the weed killer Enlist DuoTM – a combination of glyphosate and 2,4-D – in the 10 states where it is currently under consideration.[2]

The EPA should also revisit its October 2014 registration of Enlist DuoTM for use in six states because the agency considered 2,4-D and not glyphosate before finalizing its decision to allow Enlist DuoTM to be used in those initial six states. Additional concern for public health comes from emerging evidence suggesting glyphosate, 2,4-D, and dicamba may induce a changed response to antibiotics.[3]

Last year, IARC researchers demonstrated a link between exposure to 2,4-D and the cancer non-Hodgkin lymphoma.[4] The fact that the two main ingredients in Enlist DuoTM are both associated with the same cancer should only elevate concerns at EPA over the risks the herbicide poses to human health.

Glyphosate is a main ingredient in the popular agricultural weed killer Roundup®. As the amount of genetically engineered corn and soybean crops has multiplied in recent years, so has the amount of glyphosate used. Millions of acres of American farmland are being sprayed every year, and the U.S. Geological Survey has detected this “probable human carcinogen” in rain, streams and air[5] in areas where it is heavily used. It is very likely that millions of Americans inhale glyphosate during the application season. The chemical also likely contaminates rivers, lakes and reservoirs that serve as drinking water sources for millions of Americans.

When “Roundup ready” genetically engineered crops were introduced into commercial use roughly two decades ago, they were sold on the promise that they would require far less herbicide. That turned out to be an empty promise. In fact, the U.S. Geological Survey’s Pesticide National Synthesis Project found that agricultural use of glyphosate reached 280 million pounds in 2012.[6]

In addition, one recent analysis estimated that the surge in weed killer use as a direct result of genetically engineered crops has amounted to more than 500 million pounds in additional herbicides – primarily glyphosate – applied to corn, soybean and cotton fields in the U.S. between 1996 and 2011.[7] This substantial increase in glyphosate use likely poses a risk to both farm workers and those who live and work in these communities.

As a result of WHO’s rigorous and independent review, the link between glyphosate and cancer has now been greatly strengthened. No argument by the manufacturers and users of glyphosate should trump the conclusion that this toxic herbicide probably causes cancer in people. This new evidence of a serious health threat provides an additional justification for an urgent re-evaluation of glyphosate, separate and apart from the chemical’s documented ecological harm, which in and of itself is sufficient to trigger immediate review and restrictions on use.

As the EPA moves forward with its risk assessment of glyphosate in its duty to protect human and environmental health, we urge the agency to strongly weigh this action by the World Health Organization, and consider whether immediate use restrictions are necessary to protect human health and the environment.


Center for Food Safety

Consumers Union

Environmental Working Group

Food & Water Watch

Friends of the Earth

Just Label It

Natural Resources Defense Council

Pesticide Action Network North America


[1] Guyton, K.Z., et al. on behalf of IARC, 2015. Carcinogenicity of Tetrachlorvinphos, Parathion, Malathion, Diazinon, and Glyphosate. The Lancet Oncology. doi: 10.1016/S147-2045(15)70134-8.

[2] U.S. Envtl. Prot. Agency, Evaluation of 2,4-D Choline Salt Herbicide on Enlist Corn and Soybeans, Docket ID: EPA-HQ-OPP-2014-0195,!docketDetail;D=EPA-HQ-OPP-2014-0195 (last visited Mar. 23, 2015).

[3] Kurenbach B, Marjoshi D, Amábile-Cuevas CF, Ferguson GC, Godsoe W, Gibson P, Heinemann JA. 2015. Sublethal exposure to commercial formulations of theherbicides dicamba, 2,4-dichlorophenoxyacetic acid, and glyphosate cause changes in antibiotic susceptibility in Escherichia coli and Salmonella enterica serovar Typhimurium. mBio 6(2):e00009-15. doi:10.1128/mBio.00009-15.

[4] Schinasi L and ME Leon.  2014.  Non-Hodgkin Lymphoma and Occupational Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients:  A Systematic Review and Meta-Analysis. International Journal of Environmental Research and Public Health, 11, pp. 4449-4527. At:….

[5] U.S. Geological Survey. 2011. Technical Announcement: Widely Used Herbicide Commonly Found in Rain and Streams in the Mississippi River Basin.  (last visited Mar. 23, 2015).

[6] USGS Pesticide National Synthesis Project, 2015. Pesticide Use Maps – Glyphosate 2012.…, (last visited Mar. 24, 2015).

[7] Benbrook, C.M., 2012. Impacts of Genetically Engineered Crops on Pesticide Use in the U.S. – the First Sixteen Years. Environmental Science Europe. 24, 24 doi: 10.1186/2190-4715-24-24.

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