Growth of a toxicological landscape

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The main ingredient in Monsanto’s pesticide Roundup (purchased by Bayer in 2018) is a chemical called glyphosate. Glyphosate has been around since the 1970s and has been marketed as being able to kill nearly every weed, without causing harm to people or the rest of the environment.

In 2014, Dewayne Johnson was diagnosed with non-Hodgkin’s Lymphoma (a cancer of the lymphatic system). In 2015, the World Health Organization, or WHO, classified glyphosate as a probable human carcinogen. Johnson had worked as a school groundskeeper in Vallejo, regularly spraying Roundup and other glyphosate-containing pesticides. In 2018, Johnson was awarded $289 million (later reduced to $78 million) in a court case against Monsanto, as the jury found that Monsanto had been acting with “malice and oppression.” Monsanto has long insisted that Roundup is safe to use, even though the company had allegedly long been aware of the possible link to cancer.

Toxicology is well defined by the subtitle of the commonly used textbook “Casarett and Doull’s Toxicology: The Basic Science of Poisons.” Toxicologists work in many different fields, and oftentimes, people in adjacent fields will practice some aspect of toxicology without considering themselves part of the discipline. Many toxicologists also work for agrochemical companies such as Monsanto and Bayer, producing chemicals such as Roundup.

Most toxicological studies are concerned with determining how much of a substance such as glyphosate can safely be released into the environment. In the early days of pesticide production, the U.S. government did not place priority on environmental protection. The laws and guidelines that were in place were few and hard won. By the time the Clean Water (1972) and Clean Air (1970) acts were introduced, many toxic chemicals were already in the environment and were oftentimes simply “grandfathered in.” Even today, environmental health and safety data exist only for about a third of all chemicals being released. This number comes from the International Council of Chemical Associations, which estimates a circulation of about 6,000 chemicals; recent estimates from environmental health advocates hover at about 85,000.


Even today, environmental health and safety data exist only for about a third of all chemicals being released.


In the colloquium “From Medici to Macho 4.0: Masculinism and Militarism in Toxicology” held on March 18, Dr. Melina Packer, a chancellor’s postdoctoral fellow at UC Riverside’s department of gender and sexuality studies, described lack of existing toxicological information as not just “undone” science, but “undoable” science. This is dependent on both the nature of science and certain practices and methods inherent and central to toxicology.

Toxicologists interviewed by Packer called toxicology a science of “probability and prediction,” stating that it was “like forecasting the weather.” Even modern toxicology is highly limited by several factors — toxicological effects have to be observable in a lab in order to be studied, and, with ethical concerns making it impossible to test on humans, rats are often used as proxies. Furthermore, there are thousands of chemicals being released into the environment, and it would not be feasible to test all of their interactions and long-term effects.

As these experiments are often performed on rats, the toxicological data must be converted to humans — most generally the “standard human male,” which is done via mathematical formulas. The same data is used to determine the legal emission limits for toxins. Packer described these toxicological thresholds as “made up,” clarifying that while mathematical formulas were created and used to extrapolate from existing data, there was no real way to corroborate these thresholds. Early toxicologists often simply presumed that toxic effects were nonexistent or negligible because, at the time, they were unable to measure the toxic effects of certain substances, especially at low doses. Even distinguished toxicologists often interpret the same data in different ways.

Toxicology is further hampered by some of its most basic assumptions. A cornerstone of modern toxicology is the phrase “the dose makes the poison,” meaning that a substance’s toxicity is dependent on the amount someone has been exposed to. This is often modeled as a dose-response curve. Dose-response curves show how severe the response to a toxin is compared to how much of the substance was given. They are often conceptualized as sigmoid curves — if the dose is low enough, there will be little or no ill effects. As the dose increases, the ill effects worsen until they plateau (oftentimes at death).

However, according to Packer, these sigmoid curves, though convenient, simply do not model all types of toxins. Dose-response graphs created for carcinogens follow a straight line, meaning that while more of the carcinogen causes more severe effects, any amount is harmful. Further, some substances — such as endocrine disruptors, which can cause growth and reproductive dysfunction — exhibit nonmonotonic dose response. This means that in some instances, lower doses of endocrine disruptors may have more severe effects than higher doses.


Dose-response graphs created for carcinogens follow a straight line, meaning that while more of the carcinogen causes more severe effects, any amount is harmful.


All of these factors introduce a subjectivity into toxicology, which is often ignored. A second case brought against Monsanto was Hardeman v. Monsanto. Like Johnson, Hardeman had developed non-Hodgkin’s Lymphoma after working with Roundup.

Despite all these factors introducing subjectivity and unreliability into the field of toxicology, the judge in the Hardeman v. Monsanto case initially only allowed what was deemed scientific, “objective” evidence — meaning evidence from toxicological studies. According to Packer’s presentation, this decision ignored decades worth of evidence of agrochemical lobbying, taking the science they produced at face value. Toxicology was privileged over other ways of knowing due to its quantitative methods, meaning that as it was able to supply “hard numbers,” it was deemed more reliable than more qualitative sources. It was implied to be completely neutral. All scientists bring their biases, and, in toxicology, these biases and conflicts of interest are especially strong. One of Packer’s interviewees described industry infiltration as “an open secret,” and even scientists, especially in academia, did not want to speak about them due to fear of retaliation.

Despite toxicology’s assumed higher reliability due to its quantitative nature, many agrochemical companies allegedly make clever use of toxicology’s uncertainty. One of Packer’s interviewees said that uncertainty may be “weaponized.” Agrochemical companies, as Packer expanded, often use similar playbooks to the tobacco industry or climate change deniers when making their cases. So, for example, even though the WHO has classified glyphosate as a probable human carcinogen, the American Cancer Society has stated that with most cases of lymphoma, the direct cause is unknown, which can be pointed to by agrochemical companies to absolve themselves of guilt and consequences. This ignores the inherent limitations of science, which can never fully confirm a hypothesis and can only provide evidence.

In writing of their own history, as explained by Packer, who researched this aspect of toxicology by conducting close readings of textbooks, toxicologists often simply ignore harmful consequences of the events they view as seminal. For example, the Manhattan Project is described in one textbook as having “created a fertile environment” for science, but no attention is paid to the tragic effects of this development. The same textbook also celebrates DDT, an insecticide infamous for its negative impacts on environmental and human health. More generally, the book emphasizes the number of chemicals synthesized since the 1880s but does not reflect on the frequent catastrophes.

Even though modern toxicology began in the 20th century, today’s toxicologists often trace the origins of their discipline back to Paracelsus. Paracelsus was a physician, scientist and alchemist who lived from 1493 to 1541. He is especially important as the coiner of the ever-important maxim, “the dose makes the poison.” Textbooks also may include examples of how Indigenous peoples used poison to hunt or as weapons. By doing so, the textbooks mythologize and thereby normalize poisons which, in Packer’s analysis, serve to soften the “unequal exposure” to toxins and make poisons become “more palatable.” The book’s writing of history is also generally centered on men and Europe — women are often referred to with paternalistic language; the “Medici” in the title of Packer’s talk refers to Catherine de’ Medici, a poisoner who purportedly conducted human experiments in the Middle Ages. “Toxicology: the basic science of poisons” refers to her as “Catherine” on several occasions.

In this vein, it is also important to consider who the founding toxicologists were and how they saw the world. They were mostly well-off white men who could afford to pursue science as a career. Even today, this origin still influences toxicology in several different ways.

White men in science benefit from this identity. In this context, Packer brought up the concept of the “god trick,” coined by feminist science studies scholar Donna Haraway in 1988. Science is often interpreted as if the scientist were some disembodied, neutral god, which of course is not true. Nonetheless, this assumption is generally accepted for white men in science by the public. Packer stated that often people who fail to meet this standard are expected to shift their perspectives to that of white men to “remove their biases.” This goes hand in hand with the privileging of toxicology over environmental justice activists and scholars. Not only that, but healthy, adult (white) men are also the standard for whom toxicological data is calculated, as discussed previously.

In the same way that the harmful effects of the Manhattan Project and of DDT are minimized, so is the toxicologist’s role in creating toxins. Toxicology experienced major booms following the world wars. For each world war, noxious gases had been developed, and many new chemicals synthesized. By measuring and quantifying the toxic effects of these new chemicals, toxicologists enabled the peacetime use of these substances. This quantification via toxicology made these poisons seem controllable and safe. A textbook studied by Packer describes humans as “smart, but vulnerable.” To Packer, this felt like a paternalistic way of saying: Don’t worry, we toxicologists will protect you. This fails to explain that these toxins were created and are sold by petrochemical companies and clears these companies from blame. Packer referred to this as the “devil trick,” in reference to the aforementioned “god trick” — the creator of these poisons is treated as if they were some disembodied spirit, which allows the release of toxins to be “cast as inevitable.” Toxicology is then able to define a toxic substance as safe or unsafe, which essentially allows toxins to become “depoliticized” and be framed as a purely scientific issue.


Toxicology experienced major booms following the world wars. For each world war, noxious gases had been developed, and many new chemicals synthesized.


Further, Packer explains, the founding toxicologists were, due to their social status, very far removed from the people and spaces where the toxins would be used. This allowed them to quantify and declare as acceptable certain risks, safe in the knowledge that they would not be exposed to the same high levels of toxins as farm or factory workers. Packer continued that in her close reading of toxicological texts, there seemed to be an implicit acceptance of higher toxic impacts on people with less social power. This, in some sense, explains the lack of full testing and the arbitrariness of safety limits for toxins. Due to a lack of women in the early years of the discipline, there was also a pronounced lack in studies of reproductive toxicity.

When asked how this feeds into the concept of toxic masculinity, Packer referenced a previous talk she had given titled “Toxin Masculinity.” She highlighted the military origins of toxicology and its importance to the agrochemical industry, which is based around capital accumulation and land acquisition. She also emphasized an idea present in a lot of Western science — that man can control nature. Even though a lot of the chemicals released into the world are not necessarily natural, an assumption still exists in toxicology that, if careful enough, man can fully control them.

This focus on the masculinist and the militarist is also baked into how toxicology is marketed today. Many pesticides have hyper-masculine names: Roundup, Pounce, Reaper, Macho 4.0, etc., which is referenced in the title of Packer’s talk. Packer also explained with a smile that the pesticide industry conventions she attended were frequented by men dressed in cowboy clothing.

This inherent uncertainty in toxicology in combination with the discipline’s historically masculine and militarist roots has created the landscape of the discipline today. A landscape in which only about a third of the chemicals being released into the environment have been tested for environmental and human health impacts. A landscape where a company can sell a known carcinogen and tell the people that will be spraying it that it is harmless. Caught up in this system is the way in which the United States approaches chemical regulation. It practices what Packer referred to as an “after-market approach” to regulation, only fully testing and removing products after they have caused harm. Many toxins, however, never really leave the environment, making this testing crucial, yet undoable.

The judge presiding over the case Hardeman v. Monsanto eventually did allow nonscientific evidence in the form of documents supporting the allegations that Monsanto suppressed data showing the carcinogenic effects of glyphosate. This approach mirrors Packer’s conclusion on how toxicology should be treated — it should only be one of many pieces of evidence used and be couched in its context. Packer also highlighted the importance of listening to environmental justice activists, many of whom come from areas and communities where the chemicals produced by agrochemical companies have caused the most harm. The history of toxicology has encumbered the discipline with baggage, which still affects how it is being used today. To broaden the scope of how we talk about poisons and toxins, and to build a system in which it is harder for companies such as Monsanto to market carcinogenic toxins as harmless, we must start viewing lived experiences and qualitative evidence on equal terms with toxicology.

Contact Mikkel Nagorsen at [email protected]