Exploring the complex relationship between herbicide science, corporate influence, and evidence-informed public health policy.
Imagine a chemical so effective that it revolutionizes farming worldwide, only to later become the center of multi-billion dollar lawsuits and scientific controversy. This isn't a hypothetical scenario—it's the story of modern herbicides, common chemicals that have sparked a silent public health debate happening in our farm fields, regulatory agencies, and courtrooms.
Glyphosate is the world's most widely used herbicide, with millions of tons applied annually across agricultural and residential settings.
By 2019, Bayer AG faced over 13,000 lawsuits from people alleging glyphosate-based herbicides caused their non-Hodgkin lymphoma 1 .
The widespread use of herbicides has become a cornerstone of modern agriculture, enabling farmers to protect crops and feed growing populations. Yet beneath this practical success lies a complex web of scientific disagreement, corporate influence, and pressing public health questions. The case of glyphosate, the world's most widely used herbicide, illustrates a critical challenge: how do we translate scientific evidence into policies that truly protect human health when powerful economic interests are at stake? This article explores the intricate dance between emerging science, evidence-informed policy-making, and the corporate forces that can shape what we know about the chemicals in our environment.
Simply put, evidence-informed policy occurs when decision-makers use the best available evidence to guide regulations and laws 1 . In an ideal world, independent scientists would produce robust research, policy-makers would objectively evaluate these findings, and regulations would reflect scientific consensus. Reality, however, is far more complicated.
The process typically involves several steps: hazard identification (can this substance cause harm?), exposure analysis (how are people exposed?), risk assessment (what's the likelihood of harm under real-world conditions?), and risk-benefit analysis (do the benefits outweigh the risks?) 1 . This process seems straightforward until science becomes uncertain, or worse—when it's manipulated.
Hazard identification determines whether a substance can cause harm, while risk assessment evaluates the likelihood of harm under specific exposure conditions. This distinction explains why agencies sometimes reach different conclusions about the same chemical.
The debate around glyphosate, the active ingredient in Roundup, perfectly illustrates this complexity. In 2015, the International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization, classified glyphosate as "probably carcinogenic to humans" after an extensive review by independent experts 1 . The IARC evaluation applies rigorous procedures for scientific review and is conducted by experts free from conflicts of interest 1 .
| Organization | Classification | Assessment Type |
|---|---|---|
| IARC (WHO) | Probably carcinogenic | Hazard-based |
| European Food Safety Authority | Unlikely to pose risk | Risk-based |
| U.S. Environmental Protection Agency | Not likely carcinogenic | Risk-based |
| Agency for Toxic Substances | Potential cancer hazard | Hazard-based |
Meanwhile, other regulatory bodies reached different conclusions. The European Food Safety Authority (EFSA) and the U.S. Environmental Protection Agency (EPA) asserted that glyphosate poses no significant public risk 1 . How can reputable scientific organizations examining the same evidence reach such different conclusions?
Creating doubt about scientific evidence to delay regulation
Hiring writers to draft scientific papers signed by academics
Cozy relationships between industry and regulators
The once-confidential "Monsanto Papers" revealed that the company orchestrated an extensive campaign to discredit the IARC evaluation, the scientists involved, and the organization itself 1 . Internal documents showed company executives planning this response even before the March 2015 evaluation meeting took place 1 .
These documents exposed company scientists casually discussing "ghost-writing" scientific papers and suppressing research that conflicted with corporate assertions of Roundup's safety 1 .
Rather than conducting proposed long-term product safety studies, the company spent millions on secretive public relations campaigns—including $17 million in one year alone—to finance ghost-written studies and editorials aimed at discrediting independent scientists whose work had found dangers with their products 1 .
Ghost-writing involves having professional writers draft scientific papers that are then signed by academics who may have contributed little to the research or analysis. These controversial ghost-written papers were subsequently presented as independent evidence in regulatory processes 1 . This strategy isn't new—the tobacco industry perfected similar tactics for decades, successfully delaying regulation by creating scientific uncertainty about the health risks of smoking 1 .
Further complicating the picture are the cozy relationships between industry and regulatory bodies. The International Life Sciences Institute (ILSI), an organization that purports to work for health and wellbeing, has received donations exceeding $1 million from Monsanto and its industry representative CropLife International 1 . Despite these financial ties, the chair of ILSI's Board of Trustees chaired the UN's joint Food and Agriculture Organization/World Health Organization meeting that found glyphosate to be "probably not carcinogenic to humans"—a conclusion strikingly different from IARC's 1 . The final meeting report included no conflict of interest statement 1 .
The tactics used by the herbicide industry mirror those previously employed by the tobacco and lead industries, where scientific uncertainty was deliberately manufactured to delay regulation and protect profits despite known health risks.
While not a single laboratory experiment, the IARC Monographs programme represents one of the most comprehensive scientific evaluations of potential carcinogens. For almost half a century, this program has been the premier global resource for identifying agents that cause cancer 1 . The process brings together independent international experts who review all available scientific evidence according to rigorous, pre-established criteria.
The IARC evaluation follows a meticulous, multi-step procedure:
Chemicals are selected based on evidence of human exposure and suggestions of potential hazards.
All published and unpublished relevant studies are assembled, including toxicological, epidemiological, and mechanistic research.
Independent expert working groups evaluate the strength of evidence for carcinogenicity across three categories.
Experts reach consensus on classification based on pre-defined criteria.
Detailed monographs are published explaining the scientific basis for conclusions.
| Group | Description | Examples |
|---|---|---|
| 1 | Carcinogenic to humans | Tobacco, asbestos |
| 2A | Probably carcinogenic | Glyphosate, shiftwork |
| 2B | Possibly carcinogenic | Lead, coffee |
| 3 | Not classifiable | Tea, mercury |
| 4 | Probably not carcinogenic | Caprolactam |
For glyphosate, the IARC working group classified the herbicide as "probably carcinogenic to humans" (Group 2A) based on several key findings 1 :
Of carcinogenicity in humans for non-Hodgkin lymphoma
Of carcinogenicity in experimental animals
For two key characteristics of carcinogens: genotoxicity and oxidative stress
This classification placed glyphosate in the second-highest risk category out of four tiers. Importantly, the IARC evaluation constitutes a 'hazard evaluation'—it identifies whether a substance can cause cancer under any circumstances, not the level of risk under specific exposure conditions 1 . This distinction is crucial for understanding the different conclusions reached by various agencies.
The scientific debate has played out dramatically in courtrooms. By May 2019, a California court had ordered Bayer AG (which acquired Monsanto) to pay $2 billion to a couple who claimed their cancers were caused by years of using Roundup 1 . This was the third consecutive legal loss for the company, which saw its market value plummet to $52 billion—nearly half of what it was before acquiring Monsanto 1 . More than 13,000 similar claims have been lodged by people alleging the herbicide caused their non-Hodgkin lymphoma 1 .
Manufacturers often claim their products are "safe if used properly," but this raises practical questions 1 . What constitutes "proper use" of a herbicide? For agricultural workers spraying fields, avoiding exposure can be challenging. Occupational exposure may occur through inhalation, dermal contact, or ocular contact during manufacture, transport, use, and disposal 1 . The general population may be exposed through consumer products, crops, foliage, or soils containing chemical residues 1 . As a result of widespread usage, glyphosate is present at low levels in a wide range of food items 1 .
Farmworkers, landscapers, and groundskeepers face the highest exposure risks through mixing, loading, and applying herbicides, as well as through post-application activities in treated areas.
The general population is primarily exposed through diet (residues in food and water) and residential use of herbicide products for lawn and garden care.
Understanding herbicide impacts requires sophisticated research methods. Scientists use various approaches to evaluate how herbicides behave in the environment and affect biological systems.
Soil column studies, runoff simulation, leaching tests determine herbicide movement and persistence in environment.
In vitro cell assays, animal bioassays, epidemiological studies assess health impacts on organisms and humans.
Soil microbiome analysis, non-target species monitoring evaluate effects on ecosystems and biodiversity.
Biomonitoring, environmental sampling, dietary surveys quantify human and environmental exposure levels.
Genotoxicity tests, oxidative stress markers, receptor binding assays identify biological pathways affected by herbicides.
Cohort studies, case-control studies examine patterns and causes of health effects in human populations.
Laboratory experiments provide precise information because researchers can control environmental conditions and isolate specific factors 6 . However, real-world conditions often differ significantly from controlled laboratory settings, which is why multiple research approaches are necessary to fully understand herbicide impacts.
The case of glyphosate and other controversial herbicides reveals the complex interplay between science, policy, and corporate influence. When scientific evidence becomes a battlefield for economic interests, public health can become collateral damage. The tactics used to undermine independent science—ghost-writing, reputation attacks, regulatory capture—are not unique to herbicides but represent a modern challenge for evidence-informed policy-making.
For evidence-informed policy to truly serve public health, we need greater transparency in scientific research, robust conflict-of-interest policies, and recognition that creating doubt about science is a powerful political and economic strategy.
As consumers and citizens, we play a role in demanding policies that prioritize long-term public health over short-term profits. The story of herbicide regulation reminds us that what we don't know can hurt us—and that sometimes, what we're told we know has been carefully crafted by those with much to lose.