Chemicals, courts and cancer: the glyphosate conundrum

“Enlightened” modern people look down on their “foolish” predecessors. History is full of once popular notions that were beyond dispute, such as: The earth is the center of the universe. Digging holes causes rain. Witches were as thick as gnats in Salem. Women are less than men. Rodents spontaneously form. Brussels sprouts contain evil spirits. The earth is flat. The moon landing was faked.

Ignaz Semmelweis, a Hungarian doctor recommended health care workers wash their hands when delivering babies. He was scorned and committed to a mental asylum where he was beaten severely as part of his treatment. He died due to this “advanced” medical treatment within days. Birth mortality remained high until soap was finally embraced.

Luckily, the future will see us as the first completely rational generation.

Well, maybe not. Every generation is guilty, including ours. Which of our ridiculous notions will future generations mock?

Chemical vs. natural

We suggest the popular view that “chemicals are bad, natural is better” is not backed by facts.

Everything in the universe is made of matter, which are the chemical elements on the periodic table. One of these chemicals is oxygen. Wait . . . oxygen is a chemical? Yes, oxygen, which we all need to live, is a chemical.

Arsenic is also a chemical. And, like oxygen, is found in every human body. It’s natural and thus, it must be good for us. Right? After all, it was used as a medicinal product in the past. However, it is poisonous if the dose is too high. But, so is water. Yes, if you drink too much water you will die. Too much of a chemical, even water, is not good.

But water and oxygen are “natural” and, thus, good. Artificial chemicals, on the other hand, must be bad (because natural sounds better and artificial is offensive). For example, most soaps are not naturally occurring but, rather, are artificially manufactured. Thus, soap = bad. Right? Dr. Semmelweis and a mountain of scientific data would say otherwise.


Like arsenic, a heavy dose of weeds is bad for society. Invasive noxious weeds are a global problem in native ecosystems. Weeds have a cost of ~4 billion (USD), but an estimated 20 billion without herbicides. Science shows weeds hurt yields and high yields are needed to provide the food, fuel, and fiber for the 7+ billion people on this planet. Not only do weeds have an economic cost, but the reduction of crop yields costs lives due to starvation and malnutrition, especially in developing nations. Weed control saves lives.

So, how do we control weeds? Hand pulling is one option, but do it and you’ll realize that the weeds will win this battle. We’ve developed chemicals (herbicides) for weed control. One of the most significant discoveries in the war of weeds happened ~40 years ago when glyphosate (RoundUp) was discovered. This very effective broad-spectrum herbicide has been widely used in agriculture, the urban landscape, and beyond. Very popular . . . until recently.         


The wave of public opinion against glyphosate is approaching tidal wave proportions due to cancer concerns. It is an artificial chemical and, thus, it must be bad for us is the conventional wisdom. Recent court rulings have decreed such. Thus, it must be true . . . just as the courts convicted the witches of Salem. Courts are never wrong. Let’s examine the overwhelming scientific facts ignored by these courts (Figure 1).

The tide turned against glyphosate recently due to court rulings in California in favor of a fellow sports field professional and against glyphosate. This man contracted non-Hodgkin’s lymphoma. We join with him in his concern for health and in no way want to minimize this terrible disease and its effects on him and his family. However, we argue the ruling ignored facts and was injudicious.

The smoking gun

The findings of this study are in contrast with a report by the World Health Organization (WHO) International Agency for Research on Cancer (IARC). Let’s examine this report that stirred the trouble for glyphosate.

IARC, which is not a regulatory agency, issued its report in 2015, categorizing glyphosate in their Group 2A, which is defined as “probably carcinogenic to humans” (i.e. having the potential to cause cancer). The panel felt that the evidence of carcinogenicity in experimental animals was sufficient, despite evidence in humans being limited or non-existent. The IARC report did state there was no evidence for harm from exposure through food.

For context, other substances (and activities) that have received this same classification as “probably carcinogenic” include emissions from high temperature frying, red meat, very hot beverages, being a hairdresser, or participating in shift work. Note that of over 1,000 items and activities evaluated, this panel only found 1 to be “probably not carcinogenic to humans.”

Also note that many items were classified in Group 1, which is “carcinogenic to humans.” One of these is tobacco smoking, which isn’t a surprise. But another is alcoholic beverages. We find it curious that about 70% of Americans report annually ingesting a Group 1 carcinogen (according to IARC) and yet a lower risk Group 2A chemical is resulting in near mass hysteria.

The IARC assessment has other significant problems, including:

  • exposure levels were not taken into account,
  • all the available data was not used,
  • reported conflict of interest by those conducting the assessment,
  • failure to interpret research reports correctly, and
  • lack of transparency when the results were challenged.

Dr. Christopher Portier, an activist for the Environmental Defense Fund, was elected chair of the IARC Glyphosate Monograph Advisory Panel. Shortly after participating in the IARC panel he signed a contract with two firms suing Monsanto. Dr. Portier claimed later that “no one had paid him a cent” and that he “had no conflict of interest whatsoever.” It is possible that Dr. Portier did nothing wrong in his work as chair, but to say that there was no conflict of interest and that he had not been paid is untrue.

The IARC panel was biased in their selection of data used in their report. Members of the committee knew of data that showed a lack of correlation between glyphosate and cancer. Yet, these data were omitted from the evaluation. As a result, the committee did not arrive at a conclusion corroborated by science.

It appears the IARC committee also chose to change the conclusions of some scientific reports. In some of the original research papers, authors concluded their work saying that glyphosate was not carcinogenic, but the IARC provided a different conclusion stating that these studies could not be evaluated for various reasons. Research showing glyphosate was not carcinogenic was downplayed and minimized in the IARC report.

The combination of these actions by the IARC Working Group adds up to a compromised report. After the glyphosate report was released, many independent scientists were surprised, and challenged the IARC to provide greater transparency as to how the link to cancer was established. The IARC responded by claiming the scientists involved had no responsibility to answer any additional questions . . . a surprising change to the scientific method that normally embraces critique.

Trouble in WHOville

Typically left out of media coverage of the IARC report is that there were four separate WHO programs that evaluated glyphosate. The IARC report was in contrast with the other three, which include:

  • Joint Food and Agriculture Organization (FAO) and WHO Meeting on Pesticide Residues,
  • International Programme on Chemical Safety, and
  • Guidelines for Drinking-Water Quality.

These WHO programs determined that glyphosate is “not carcinogenic.” Only one of the WHO evaluations, the IARC report, found glyphosate to be potentially carcinogenic . . . along with doing shift work and being a hairdresser.

In God we trust, all others bring data

Are there studies showing that glyphosate is unsafe? Yes, but there are very few of these and a careful vetting by unbiased experts suggests these studies are flawed. For example, one study claimed a 41% increase in cancer, but an excellent analysis of the methods showed this to be a faulty study where significant amounts of data were omitted, as documented at

A plethora of high quality, independent research has been done showing glyphosate is not carcinogenic. There have been more than 800 independent studies on glyphosate. It is one of the most studied chemicals in history. Yet none prove carcinogenicity or other deleterious effects if used according to label. Perhaps the most robust study is the Agricultural Health Study. Over 54,000 workers from Iowa and North Carolina participated in this study. The authors of this research were able to control for exposure to other pesticides. They found no positive association between glyphosate and cancer.

Regulatory agencies

Global Regulators and Advisory Groups, as well as others (approved in over 160 countries), have ruled glyphosate neither carcinogenic, mutagenic, nor reprotoxic. Recently, Health Canada stated that concerns about glyphosate safety are not supported by science when considering “the entire body of relevant data.” Shortly after, the US EPA reaffirmed that glyphosate is not a carcinogen. They state that their evaluation was “more robust” and “more transparent” than the IARC report. They stated, “There is no risk to public health from the application of glyphosate.”

In stark contrast to the lack of transparency surrounding the IARC report, the EPA evaluation is freely available to the public. Panel members and procedures are listed. The report addresses and summarizes all the available scientific findings. The EPA report also lists questions and concerns that were raised by panel members.

In August 2019, the EPA issued labeling guidelines to ensure clarity stating that they will no longer approve labels claiming that glyphosate causes cancer (due to Proposition 65 in California making such claims and requiring their own labeling).

Fact or fiction?

Despite the overwhelming evidence and near full consensus by unbiased experts, recent court rulings relied heavily on the IARC classification, which has caused this frenzy against glyphosate. Advertisements are widespread asking for anyone exposed to this chemical to join the throngs of class action lawsuits. Insurance companies are beginning to deny coverage for those who use glyphosate. Etc.

The answer? Stop using glyphosate and use natural or organically certified herbicides, such as household vinegar. Unfortunately, vinegar is not really natural. And, it doesn’t work very well as an herbicide. And, you have to use the concentrated form (acetic acid) for it to have any effect. And, the scientifically measured toxicity of vinegar for human exposure is actually worse than glyphosate. Many common chemicals have higher toxicity than glyphosate. Just like we use water appropriately, we use chemicals with toxicity according to safe instructions at the right dosage. For example, antibiotics are pesticides (chemicals that kill pests) and safe when used appropriately. The actual facts show that countless lives have been saved by these medicines and, yet, even these are being falsely scrutinized because they are not “natural.”

Every regulatory agency in the world that examined the link between glyphosate and cancer concluded there is no link. Yet, the people who manufacture and market this important chemical are struggling and we are at risk of losing the use of this valuable resource because of the foolish notions of the masses and a single misguided report that gets more press than all of the others combined.

Society will be better served when the general public is well informed by facts. The scientific method is not without flaws or bias, but the truth is eventually ferreted out. We need to understand that not all artificially manufactured things are bad for us. The fact is that pesticides and fertilizers have been among the most important contributors of the Green Revolution of the past few decades, resulting in great increases in lifespan and quality of life. We do need to exercise caution by properly evaluating chemicals and then using them according to safe instructions. Let’s not be the generation that regressed from innovation. Or the next thing might be beatings for shift working hairdressers that use soap.

Bryan G. Hopkins, PhD, is a professor at Brigham Young University, Provo, UT; Jeff S. Miller, PhD, is president of Miller Research, Rupert, ID; Emily Neilson is a research assistant at BYU; and Bradley D. Geary is a professor at BYU. For references see