EWG, Scientists and Doctors Sign Letter Urging EPA To Reject Potent Herbicide Mix

Administrator Gina McCarthy

U.S. Environmental Protection Agency

1200 Pennsylvania Ave

NW Washington, DC 20460

RE: Dow AgroSciences application to amend their 2,4-D choline salt herbicide for use on 2,4-D tolerant corn and soybeans. Docket EPA-HQ-OPP-2014-0195

Dear Administrator McCarthy:

We the undersigned scientists, medical professionals, and researchers are writing to urge the U.S. Environmental Protection Agency not to register a double herbicide mix of 2,4-D and glyphosate (the “Enlist DuoTM” weed killer) for farm field spraying in combination with a new breed of genetically engineered corn and soybeans.

This 2,4-Dichlorophenoxyacetic acid (2,4-D) and glyphosate herbicide system developed by Dow AgroSciences, a wholly owned subsidiary of the Dow Chemical Company, would put public health at risk if sprayed on millions of acres of cropland.

Dow Chemical Company promotes 2,4-D-resistant corn and soybeans to be used in conjunction with Enlist DuoTM because the widespread planting of the glyphosate-tolerant Roundup Ready corn and soybeans has resulted in accelerated herbicide resistance in numerous weed species. Now, instead of re-evaluating the genetically engineered crop strategy in the United States, the U.S. Department of Agriculture and EPA are close to approving the 2,4-D-resistant corn and soybeans despite the risks that the increased use of 2,4-D would pose to human health and the environment.

2,4-D is a notorious herbicide that has been linked with adverse health effects to the thyroid2 and an increased risk of non-Hodgkin’s lymphoma in human epidemiological studies. Although studies of pesticide exposure among farmers and their families are confounded by exposure to multiple pesticides, there is a large and compelling body of data that demonstrates the link between occupational exposure to herbicides and insecticides and non-Hodgkin’s lymphoma. Studies of farmers who worked with 2,4-D found a link between exposure to this herbicide and suppressed immune function, lower sperm count, and a greater risk of Parkinson’s disease.

These findings from human studies, whether small-scale, pilot studies or large cohort studies, point out significant risks from 2,4-D to human health even for the relatively healthy adults who work in agricultural jobs. Such risks would be much higher for young children, especially young children in residential communities, schools, and daycare centers near the 2,4-D-sprayed fields.

Also worrisome is the fact that the manufacturer did not conduct any toxicity tests for simultaneous exposure to the combination of 2,4-D and glyphosate, which could pose a much higher human and environmental toxicity risk than either herbicide alone. EPA acknowledges that, “there could be additional toxicological effects (synergistic or additive) because of the presence of two herbicides.”Yet, the Agency disregarded these data gaps and both human and environmental toxicity concerns in its proposal to register the Enlist DuoTM herbicide.

If the EPA were to approve Dow’s application for 2,4-D-glyphosate herbicide to be used on 2,4-D-resistant crops, USDA estimates at least a tripling of use of 2,4-D by 2020 compared to the present amounts used annually for agriculture in the United States.9 The increase in 2,4-D spraying on corn and soybean fields would lead to pollution of food and water and increased drift of 2,4-D from the fields into nearby residential areas. The Dow Chemical Company claims that their 2,4-D choline salt formulation has low volatility and low drift. However, the large-scale, blanket spraying that has become standard practice with genetically engineered crops would make herbicide drift from sprayed fields into nearby residential areas and ecosystem habitats highly likely to occur.

In addition to putting human health at risk, increased 2,4-D spraying would harm the already-vulnerable ecosystems in intensely farmed regions of the United States; affect dozens of endangered species; and potentially contribute to the decline of pollinators and honeybees. EPA itself has identified these likely outcomes of 2,4-D spraying in the agency’s ecological risk assessment for 2,4-D. Such direct and indirect effects of 2,4-D would have significant negative economic consequences.

Finally, increased 2,4-D application is likely to accelerate and exacerbate the evolution of yet more 2,4-D- resistant weeds. This pattern is known as the “pesticide treadmill” when farmers end up using larger amounts of increasingly toxic chemicals to control herbicide-resistant weeds eventually requiring the use of different pesticides.

Decades of research have continuously demonstrated the risks of using 2,4-D, a notoriously toxic herbicide. Allowing large-scale 2,4-D spraying in combination with 2,4-D-tolerant genetically engineered crops would worsen the problem. We urge the EPA to do the right thing and deny the approval of the new mixtures of 2,4-D and glyphosate in order to protect human and environmental health.


Toni Bark, M.D., MHEM, LEED AP
Founder and Medical Director
Center for Disease Prevention and Reversal

Charles Benbrook, Ph.D.
Research Professor
Center for Sustaining Agriculture and Natural Resources
Washington State University

Alison Bleaney, M.B., Ch.B., FACRRM
Medical Practitioner
National Toxics Network, Tasmanian Environmental Health Network, Doctors for America

David O. Carpenter, M.D.
Institute for Health and the Environment at Albany

Lynn Carroll, Ph.D.
Senior Scientist
TEDX, The Endocrine Disruption Exchange

Margaret Christensen, M.D., FACOG
Adjunct Faculty, President
Institute for Functional Medicine, Christensen Center for Whole Life Health

Theo Colborn, Ph.D.
President Emeritus
TEDX, The Endocrine Disruption Exchange

Johanna Congleton, MSPH, Ph.D.
Senior Scientist
Environmental Working Group

Martin Donohue, M.D., FACP
Adjunct Associate Professor; Member; Senior Physician
School of Community Health, Portland State University; Social Justice Committee & Board of Advisors, Physicians for Social Responsibility; Internal Medicine, Kaiser Sunnyside Medical Center

Diane Drum, R.N., AE-C
Multnomah County Environmental Health

Mary Eubanks, Ph.D.
Adjunct Professor
Dept. of Biology, Duke University

Elizabeth Frost, M.D.
Medical Practitioner
Hennepin County Medical Center (HCMC)

Robert M. Gould, M.D.
San Francisco Bay Area Chapter, Physicians for Social Responsibility

Michael Hansen, Ph.D.
Senior Scientist Consumers Union

Carol Kwiatkowski, Ph.D.
Executive Director
TEDX, The Endocrine Disruption Exchange

Philip J. Landrigan, M.D.
Dean for Global Health
Ethel H. Wise Professor and Chairman Department of Preventive Medicine
Professor of Pediatrics
Director, Children’s Environmental Health Center Icahn School of Medicine at Mount Sinai

Chensheng (Alex) Lu, Ph.D.
Associate Professor of Environmental Exposure Biology
Dept. of Environmental Health, Harvard School of Public Health

Rob McConnell, M.D.
Professor of Preventative Medicine University of Southern California

Margaret Mellon Ph.D., J.D.
Science Policy Consultant
Mellon Associates

Gretel Munroe, M.S., MSH, R.D.

Raymond Richard Neutra, M.D., DrPH
Retired Chief of Division of Environmental and Occupational Disease Control
California Dept. of Public Health

John A. Patterson, M.D., MSPH
Associate Professor
Dept. of Family and Community Medicine, University of Kentucky College of Medicine

Jerome A. Paulson, M.D., FAAP
Medical Director for National and Global Affairs Children’s National Health System

Warren Paul Porter, Ph.D.
Professor of Zoology, Professor of Environmental Toxicology, Invited Affiliate Faculty Member, Engineering Physics
University of Wisconsin, Madison

Julia Quint, Ph.D.
Research Scientist and Former Chief
Hazard Evaluation System and Information Service, California Department of Public Health (Retired)

James Roberts, M.D., MPH
Associate Professor of Pediatrics
Medical University of South Carolina

Johanna Rochester, Ph.D.
Research Associate
Hazard Evaluation System and Information Service, California Department of Public Health (Retired)

Kenneth Rosenman, M.D., FACE, FACPM
Professor of Medicine, Chief of the Division of Occupational and Environmental Medicine Michigan State University

Ricardo J. Salvador, Ph.D.
Director and Senior Scientist Union of Concerned Scientists

Jennifer Sass, Ph.D.
Senior Scientist, Professional Lecturer Natural Resources Defense Council, George Washington University

Shilpa P. Saxena, M.D. President
SevaMed Institute, PA

David Shubert, Ph.D.
Salk Institute for Biological Studies

Sandra Steingraber, Ph.D.
Distinguished Scholar in Residence
Dept. of Environmental Studies and Science Ithaca College

Robin M. Whyatt, DrPH
Professor of Environmental Health Sciences Colombia Center for Children’s Environmental Health

Marisa C. Weiss, M.D.
President and Founder Breastcancer.org

The signers of this letter have done so in their personal capacities. Institutional affiliations are provided only for identification purposes and do not imply any institutional position.

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