A crop-dusting plane from Palmer Aviation Services sprays a field of corn north of Manito, Ill., in July 2011. The approval of genetically engineered crops that are resistant to 2,4-D would lead to increased use of the toxic herbicide.Ron Johnson/Journal Star/AP
While my sister-in-law put the finishing touches on Thanksgiving dinner, I listened to her friend recount the losing battle her husband, a Vietnam veteran, fought with lung cancer. She explained her husband’s illness was caused by his wartime exposure to the toxic defoliant Agent Orange, produced primarily by two companies, Dow Chemical and Monsanto. Named for the colored band on its transport tanks, Agent Orange was a cocktail of chemicals, including an herbicide called 2,4-D. Shortly after the spraying — conducted to deprive guerrilla fighters of cover and a food supply — started in 1962, reports began to emerge of serious health effects, from birth defects to other illnesses. To this day, the U.S. Department of Veteran Affairs offers an Agent Orange registry health exam for the possible long-term problems caused by exposure, and more than 40,000 veterans have submitted disability claims. The Red Cross estimates that 1 million Vietnamese were affected, including third-generation children born with severe birth defects.
In January the U.S. Department of Agriculture opened a public comment period on the environmental and health impacts of a new suite of crops engineered to be resistant to 2,4-D. These corn and soybean plants, produced by Dow AgroSciences, a subsidiary of Dow Chemical, would be the first developed to be resistant to the herbicide.
According to experts, the introduction of these new crops could cause 2,4-D use to jump, big time. Chuck Benbrook, a pesticide policy expert with the Center for Sustaining Agriculture and Natural Resources at Washington State University, has estimated that if it’s approved, the engineered corn could cause applications of 2,4-D to jump 20-fold by 2019.
That’s particularly concerning because experts have long shown that 2,4-D causes serious harm to humans, especially when used over vast swaths of farmland and lawns. Largely because of such concern, the Natural Resources Defense Council (NRDC) petitioned the Environmental Protection Agency to revoke the chemical’s approval, first granted in 1948.
NRDC researchers and other critics of 2,4-D point to studies showing the chemical is a neurotoxin and that exposure to it can cause hormone disruption, certain forms of cancer and genetic mutations. The chemical has also been linked to lowered sperm counts, liver disease and Parkinson’s disease as well as adverse effects on reproductive and immune systems. What’s further worrisome is that 2,4-D is known to drift, affecting areas near farms, including streams, rivers and wildlife.
In April 2012 the EPA rejected the NRDC’s petition, stating that the group did not prove that the chemical was unsafe in the manner it is used. Despite the EPA’s actions, public health advocates have maintained that there are serious human health impacts, based on compelling evidence from peer-reviewed studies around the world. A University of Minnesota study found a greater frequency of genetic mutations in pesticide applicators who had higher rates of 2,4-D in their urine. A National Cancer Institute study found farmers exposed to 2,4-D upward of 20 days a year had a higher risk of developing non-Hodgkin’s lymphoma than nonfarmers did, by a factor of six. The EPA’s fact sheet notes that the chemical has shown toxic effects on the thyroid and gonads and expresses concern about potential “endocrine-disrupting effects.”
With all these risks, why are chemical companies like Dow and Monsanto formulating seeds to be resistant to this decades-old chemical with a terrible health track record? The USDA said these new crops are intended to “help address the problem of weeds that have developed resistance to other herbicides.”
But what’s driving the weed resistance in the first place? In part, the widespread use of another genetically engineered technology by the same chemical companies: Roundup Ready corn and soybeans developed by Monsanto. Introduced in the 1990s, Roundup Ready corn and soybeans account for 70 and 90 percent of those crops, respectively. Since then, farmers have sprayed so much of the relatively inexpensive Roundup herbicide that weeds have been developing resistance. Roundup-resistant weeds now pose such a problem for farmers that the head of the Arkansas Association of Conservation Districts told The New York Times these superweeds are “the single largest threat to production agriculture that we have ever seen.”
But, 2,4-D-resistant genetically engineered corn and soybean seeds will lead to more weed resistance. In 2012 the trade journal Weed Science reported on new, previously undocumented 2,4-D-resistant weeds. As the new plants encourage more spraying of 2,4-D, this weed resistance will expand. This is particularly worrisome because 2,4-D is much more toxic than Roundup; it is the seventh-largest source of dioxins (PDF) in our environment, and it bioaccumulates, meaning it builds up in our bodies and in the environment over time. “If Dow Chemical’s 2,4-D-tolerant corn and soy crops are approved by the USDA, hundreds of millions more pounds (PDF) of this toxic chemical will be used on crops, with ever-increasing residues on our food,” the Center for Food Safety’s Rebecca Spector told me. And because 2,4-D can drift, even organic crops, grown by farmers who by definition do not use herbicides, are at risk from neighbors using those genetically engineered seeds.
The real motivation behind the introduction of those products is Monsanto’s and Dow’s bottom lines. Simply put, producing new herbicide-resistant seeds is one of the best ways to boost sales of chemicals. “[Genetically engineered] seeds are the growth engine of pesticide companies,” said Marcia Ishii-Eiteman, a senior scientist at the Pesticide Action Network, a coalition that seeks to replace harmful pesticides with ecologically sound alternatives. “This is the primary reason that pesticide companies began buying up seed companies in the 1980s and then engineering seeds to be used with proprietary pesticides. The profitable trend for chemical companies continues today and has kept American farmers on this pesticide treadmill.”
Decades after Agent Orange was sprayed over South Vietnam, we have borne witness to the human toll of exposure to its cocktail of chemicals, including 2,4-D. It would be wise to approach with extreme caution any regulatory action that would encourage more — not less — use of 2,4-D. What’s more, herbicide use on American farmland simply perpetuates a vicious cycle: Spraying leads to weed resistance, which leads to more spraying. The solution is to break the cycle by investing in a different kind of innovation, one that promotes ecological solutions to weed control.
On March 11, the USDA’s Animal and Plant Health Inspection Service closed its public comment period on the question of regulating these new crops. If the USDA approves the seeds, the EPA still has to assess whether and how 2,4-D should be sprayed. Until then, environmental and health advocates, such as the Center for Food Safety, are urging Americans to air their concerns about this new use of genetic engineering. It’s time we pivot from a corrosive cycle and support the kind of innovations that get decades-old, toxic chemicals off our farms, fields and lawns.