1:40 - Brent opened the episode by reflecting on how pesticides have shaped his life from the very beginning. He shared how his father worked alongside Cesar Chavez in California, supporting agricultural workers who were being poisoned on the job. Through this work, his father helped farmworkers limit their exposure and connect with medical care to detoxify the chemicals from their bodies.

Cesar Chavez was a co-founder of United Farm Workers (UFW), the largest and longest-standing union for agricultural workers in the U.S. The UFW fought to empower farmworkers to demand social justice, safer working conditions and respect in the fields where they laboured. He led major efforts in California to protect farmworkers from the dangers of pesticides. Through general strikes, marches, boycotts, and even hunger strikes, they brought national attention to the widespread poisoning of agricultural workers and pushed for stronger protections, safety standards, and regulatory oversight (source, source.

Across decades of organizing, the UFW helped secure contracts that improved wages and included pesticide-related safeguards, challenged the chemical industry’s claims of “safe” use, and laid foundational groundwork for today’s environmental justice movement. Their work made clear that protecting the people who grow the nation’s food requires confronting the toxic systems that endanger them (source.

6:40 - Brent explained that to understand the history of glyphosate, you must first understand the legacy of dioxin contamination in earlier herbicides, particularly herbicides DDT and 2,4,5-T. These chemicals formed the foundation of modern pesticide use and were central ingredients in Agent Orange, which the United States deployed during the Vietnam War.

Between 1961 and 1971, the military sprayed an estimated 77 million liters of herbicides contaminated with TCDD, the most toxic form of dioxin, across Vietnam, Cambodia, and Laos (source. This effort, largely carried out through Operation Ranch Hand, targeted the dense forests along the Ho Chi Minh Trail in order to strip away vegetation that protected Vietnamese soldiers. The environmental destruction was immense, and exposure to TCDD led to widespread human suffering, including cancers, immune dysfunction, reproductive harm, and birth defects among both Vietnamese civilians and U.S. veterans (source).

By the late 1970s, the connection between Agent Orange exposure and long-term health complications became undeniable. Veterans filed a class-action lawsuit in 1979 against Monsanto and other producers seeking compensation for the harm caused by these chemicals. The case was settled in 1984 for 180 million dollars, one of the largest settlements of its time (source.

Despite this, pesticides contaminated with dioxin continued to be used within the United States for several years. The ingredient 2,4,5-T was not fully banned for domestic use until 1979 for food crops, with remaining applications only phased out by 1985.. Its companion herbicide, 2,4-D, remained in widespread use across American agriculture (source.

The core issue was the production process of the chemical itself. Manufacturing 2,4,5-T created TCDD as a byproduct, and TCDD is a persistent organic pollutant often described as a ‘forever chemical’. Unlike the Agent Orange mixture, which breaks down relatively quickly in sunlight when unbound, TCDD remains stable in soil and the environment for decades. It is classified as a human carcinogen and is considered the most harmful member of the dioxin family (source.

Concerns about the toxicity of dioxin were raised early in its history. Internal reports show that Monsanto scientists knew by 1962 that TCDD contamination posed serious risks. That same year, the President's Science Advisory Committee warned the Joint Chiefs of Staff about the toxicity of the herbicide components being used in Vietnam. Academic studies dating back to the 1950s also confirmed the dangers. By the time the impacts became widely known and politically unavoidable, the chemical industry was already beginning to shift its focus (source.

It was within this context that Monsanto began developing the next generation of herbicides. In 1970, company chemist John E. Franz discovered the herbicidal properties of glyphosate. Monsanto moved quickly to secure intellectual property, patenting glyphosate in 1971 and bringing it to market in 1974 under the name Roundup (U.S. Patent 3,799,758). The company promoted glyphosate as a safer alternative to older herbicides, relying heavily on the contrast with the legacy of dioxin contamination. Roundup would go on to become the most widely used agricultural chemical in history, shaping the modern landscape of industrial farming and setting the stage for the regulatory, scientific, and legal battles that continue today.

8:00 - Brent explained that glyphosate was discovered as a herbicide when scientists realized they could us it to inhibit the shikimate pathway, a biological mechanism found in plants and bacteria that is essential for growth and survival. By blocking this pathway, glyphosate is able to kill plants. To better understand how glyphosate affects plant biology through the shikimate pathway, as well as its implications for the human gut microbiome and mitochondrial function, see Ep 1: The Chemical Within with Zach Bush, MD and Ep 3: Connecting the Dots with Dr. Stephanie Seneff.

9:30 - Brent noted that glyphosate use did not skyrocket until the introduction of genetically modified (GM) soy and other crops that were engineered to withstand the chemical. These crops were altered so the shikimate pathway no longer responded to glyphosate, which allowed farmers to spray entire fields without harming the crop, killing only the surrounding weeds. Brent also pointed out that Monsanto engaged in questionable practices to ensure this technology moved through the FDA approval process unhindered.

To learn more about the relationship between GMOs and glyphosate, the corruption that occurred during the approval process, and how these technologies drove a dramatic increase in herbicide use, see Ep 4: Seeds of Control with Jeffrey Smith and Ep 7: The Long Game with Dr. Charles Benbrook.