Glyphosate and the Shadow of DDT

WRITTEN BY MICHELLE BAE

ILLUSTRATED BY CHARLOTTE CHANG

May 13, 2026 | | 8 min read
Glyphosate and Its Environmental Controversy

On February 18th, President Donald Trump signed a controversial executive order promoting and protecting the domestic production of glyphosate in the name of national defense.1 While you may not recognize the name of this chemical, you most likely have used or seen Roundup, Ranger Pro, or the many other herbicides that are made from it. Glyphosate is the most common chemical pesticide in the United States2.

Backing the order was health secretary Robert F. Kennedy Jr., usually an avid critic of agricultural pesticides including glyphosate. Ironically, he served years on a legal team that successfully sued Monsanto, the company owning Roundup, for millions of dollars for producing the product.3 Protections provided by the executive order provide more immunity for Monsanto and other glyphosate manufacturers from future lawsuits. Members of the Make America Healthy Again movement (founded by RFK Jr.) in addition to others across party lines were outraged by his apparent shift in values.4

But what is glyphosate, and what makes it so controversial? 

Glyphosate is a simple molecule which bears enough structural similarity to phosphoenolpyruvate (PEP) to bind instead of it in the active site in the EPSP synthetase. This enzyme is part of the shikimate pathway, which is needed for the production of aromatic amino acids and many pigments in plants and fungi.5 For this reason, glyphosate is highly effective in killing weeds, and it is used extensively—hundreds of millions of pounds of it per year—in the agricultural industry, commercial and home gardening, and even habitat restoration to kill invasive species.6 

However, biologists, chemists, and public health specialists do not agree on glyphosate’s effects on the environment and human health. Some studies note glyphosate’s toxicity to honeybees and attribute the herbicide to their decline, while others deny that its effect is significant.7 The International Association for Research on Cancer, a branch of the World Health Organization, categorized glyphosate a probable carcinogen in 2015, especially associated with Non-Hodgkin lymphoma.8 This decision provided the basis for the lawsuit against Monsanto in which RFK Jr. took part. In contrast, the United States Environmental Protection Agency found no carcinogenic risk when it is used as directed.9 Similarly, public opinion is split. Search online for glyphosate, and you will find news articles, blogs, and social media content either bashing it or singing its praises.

In light of contradicting studies and public opinions, how are we to proceed with glyphosate, a molecule on which we so heavily rely? A look into the past may guide our future.

The Emergence of DDT: 

The invasion of Poland by Germany and the Soviet Union in September of 1939 marked the beginning of the western theater of World War II—the years-long conflict that unveiled the radical and unforgettable depths of human cruelty, ingenuity, and resilience. 

During that same month, in the neutral country of Switzerland, chemist Paul Müller made a discovery which would also change the world. While experimenting with synthetic chemicals to replace existing pesticides, Müller laced a glass cage with a white powder he had made in the lab: dichloro-diphenyl-trichloroethane, better known as DDT. He placed flies inside the cage, and they died shortly after from nervous system failure. He then rinsed the cage with acetone, a solvent commonly used for cleaning, but flies placed inside afterwards still died from nervous failure.10 The reason wasn’t understood at the time, but decades of advancements in biochemistry have elucidated its mechanism; we now know that DDT forces sodium voltage-gated ion channels to stay open, which prevents the rapid fluxes of Na+ into the cell that are needed to transmit nervous signals.11 Although others synthesized DDT long before Müller, in 1939, he was the first to discover its capacity as a potent insecticide. 

This discovery was aptly timed. Insect-borne diseases like typhus and malaria loomed over troops in the Italian, African, and Southwest Pacific fronts of the war. Arsenic-based insecticides such as Paris Green were widely used at the time in both agricultural and military settings to control pest populations and insect-borne diseases, but their acute toxicity made them unsuitable for military hygiene purposes involving direct contact with the skin. The most effective safer alternative, pyrethrum, was significantly more expensive because it was derived from chrysanthemum flowers exported almost exclusively from Japan and Kenya.12 Following Pearl Harbor, allied powers were pressured to find pesticides to supplement their pyrethrum stocks.

Among the many alternative pesticides tested, DDT proved to be the best. It was highly efficient, relatively inexpensive, and long-lasting. DDT was used to dust over surfaces, launder clothing, and spray from planes over combat sites and refugee camps. In one instance, it was even used in an organized campaign to quell a civilian typhus outbreak in Naples (though press coverage may have exaggerated DDT’s contribution to this success).12

The Rise of DDT:

World War II’s popularization of DDT and its reputation as a safe—perhaps even heroic—pesticide paved the way for its widespread civilian use in the United States and abroad. It was sprayed on farmfields, businesses, home gardens, and even bedrooms. DDT became a lucrative business. Chemical giants like Montrose and Du Pont produced DDT domestically to meet rising demand. It is estimated that the US used 1.35 billion pounds of it in the years 1942-1972.13 

In many respects, DDT was a miracle chemical. It saved the lives of many who would have otherwise succumbed to typhus and malaria, and in the agricultural setting, DDT protected crops without subjecting farmers to insurmountable pesticide costs or heavy metal poisoning. Moreover, its resistance to biodegradation and its high insolubility guaranteed long-lasting effects (it wouldn’t leech off into waterways or groundwater after watering, just as it didn’t wash away when Muller rinsed cages with acetone). These properties explain DDT’s ubiquitous use in the United States, where it was primarily sprayed from planes over crop fields, but also used to de-bug businesses and even home gardens.14 

Unfortunately, the discovery of DDT’s vast environmental damage and threats to human health have tarnished its legacy. 

The Decline of DDT:

During DDT’s heyday, manufacturing companies produced mass quantities of toxic waste. The final step of DDT synthesis, a Friedel-Crafts acylation between trichloroacetaldehyde and chlorobenzene, produced large volumes of highly concentrated (75-85 vol %) sulfuric acid contaminated with DDT as a waste product. These companies outsourced the disposal of such waste to the California Salvage Company (Cal Salvage). Cal Salvage would board the sludge—thousands of pounds of it annually—onto boats and dump them into the Pacific Ocean, primarily into the San Pedro Basin, between Catalina Island and Long Beach.15 Remarkably, this practice was legal so long as it took place within permitted zones, though Cal Salvage often discharged additional chemical waste in unpermitted locations as well. Despite ocean dumping being unilaterally banned by the EPA in 1972, DDT is still detected regularly in water and wildlife in the San Pedro Basin due to its chemical stability.16,17

The public, however, was generally not aware of these dumping sites and the harm that they would cause to ocean life even decades down the line. One of the first more obvious warning signs was in the sky. Bird populations—especially those of apex predators like the bald eagle, California condor, and brown pelican—declined rapidly soon after DDT’s widespread adoption in United States agriculture. Their eggshells were too thin, cracking when birds sat down to incubate, but the correlation between DDT and bird reproductive failure was not understood when they seemed to have no significant interaction with one another.18

In her 1962 novel Silent Spring, marine biologist and writer Rachel Carson proposed an answer: bioaccumulation. While the concentration of DDT in one organism may not be enough to cause another harm, consumption of many such organisms would cause DDT to build up to toxic levels in the consumer. Carson explained DDT’s high solubility and stability in fats (a result of its two aromatic rings), and how this allows it to magnify up the food chain, which is why apex predators with no obvious connection to DDT were still disproportionately impacted by it. This effect, however, was not limited merely to birds. DDT and other chemicals Carson referred to as “agents of death” could also bioaccumulate up the human food chain, from DDT-sprayed crops and livestock to the kitchen table.18 

The novel was an immediate controversy. In scathing reviews, critics (including scientists) from pesticide industries and the Department of Agriculture hostilely dismissed it as unscientific and alarmist. It would take another decade before DDT was banned, but Silent Spring sealed its fate. DDT production stopped growing only a year after Silent Spring’s publication, the same year the bald eagle population in the contiguous United States reached its minimum (417 nesting pairs).19 Public approval for DDT, once a molecular war-time hero, began to wane. President John F. Kennedy commissioned a team to investigate Carson’s claims, and confirmed them to be true. Scientific studies conducted after Silent Spring have provided consistent evidence that DDT is associated with causing liver cancer, type two diabetes, respiratory issues in children and infants, and reproductive effects.20

The Legacy of DDT:

In 2007, thirty-five years after DDT was banned, the bald eagle was removed from the endangered species list. DDT exposure to both humans and the environment has dropped dramatically. While a few countries still use DDT to control malaria and visceral leishmaniasis, potentially fatal insect-borne diseases, its popularity has faded globally both because of evolved resistance, environmental concerns, and the development of better alternatives.14 DDT, perhaps the most revolutionary pesticide invented to date, is now in its twilight.

DDT enjoyed wild popularity after its international debut in World War II. In certain cases, its use was life-saving and necessary. It was critical in the eradication of malaria in Europe, and it eliminated the need for heavy metal based pesticides, which were themselves potent environmental toxins. However, without extensive scientific research, it was advertised by

companies with bright illustrations of smiling children and catchy slogans such as “DDT is good for me” while it was actively causing reproductive harm and liver cancer in consumers. Tens of millions of pounds of it were produced and spread over farms and homes in the United States annually, and it brought iconic species like the bald eagle and the California condor to the brink of extinction. 

Glyphosate and DDT have stark differences. Glyphosate is an herbicide, while DDT is an insecticide. Glyphosate is far less toxic than DDT, just as DDT was relative to its heavy metal-based predecessors like Paris Green. And yet, their stories share uncanny parallels. Glyphosate is the agricultural industry’s newest “miracle” chemical, hailed for improving crop yields at relatively low costs to farmers. The passing of an executive order to protect its domestic production in the name of “national security” frames glyphosate in the same heroic light as the press coverage of DDT quelling typhus in Naples. While glyphosate has real and significant merits (just as DDT did), DDT’s legacy forces us to (re)consider the potential price of questioning the environmental and health effects of a chemical only after its widespread adoption. DDT’s legacy forces us to consider when the use and promotion of glyphosate are justified. The merits of glyphosate must not obscure the studies by large international agencies that have linked glyphosate to Non-Hodgkin lymphoma and to the decline of pollinators. Should it still be distributed in products such as Roundup to school groundskeepers and commercial gardeners, who often handle the substance in large quantities without being supplied proper PPE? Should it be sprayed over crop fields by the tons while honeybee populations continue to decline? Should its domestic production and distribution be protected by an executive order, defending glyphosate’s dominant share of herbicide sales while disincentivizing innovation to develop diverse and potentially better alternatives? DDT tells a tale of caution: what may seem to be a good thing could very well come back to bite us when we fail to clearly understand and define the stakes.

References
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