Story Behind The Round-Up Lawsuits

The first “toxic tort” case involving herbicide and a large number of victims was Agent Orange. Vietnam veterans and their children sued the manufacturers of the defoliant, which was heavily sprayed in North Vietnam in the 1960s and 1970s. The lengthy, complex litigation surrounding Agent Orange set the stage for future toxic tort cases against chemical manufacturers.

In 2016, the first lawsuit was filed against Monsanto, claiming that the popular weed killer Roundup caused cancer. Although no definitive link was ever made between the claimant’s cancer and glyphosate, the active chemical in Roundup, the claimant won the case on the grounds that Monsanto “failed to warn” of potential risks. Since then, Roundup lawsuits have been filed at an increasing rate.

The Problem with Roundup

Roundup herbicide has been in use worldwide since 1974. It was manufactured by Monsanto and originally designed to kill broadleaf weeds in corn and wheat fields. After Bayer bought out Monsanto in 2018, they continued to produce the herbicide under the Roundup name.

The active ingredient in Roundup is the chemical glyphosate. Glyphosate is a “non-selective” herbicide, meaning it kills most plants. It works by blocking an enzyme that plants need for synthesizing the amino acids they need to grow. Because of how glyphosate interacts with plants, it can kill weeds without harming crops, making it highly desirable for farmers.

The enzyme blocked by glyphosate does not exist in humans or animals, so the herbicide was believed to be safe for humans as long as normal precautions were used during application. However, when inhaled or absorbed through the skin, the compound was no safer than any other chemical.

Roundup Ready Crops and GMOs

Weeds are like any other pest. They develop immunity to poisons being used against them. Unfortunately, the weeds targeted by Roundup developed resistance to glyphosate, meaning either stronger herbicides needed to be developed or heavier concentrations of Roundup needed to be used for the same effect.

In 1996, Monsanto introduced “Roundup Ready” soybeans. These genetically-modified crops contained an artificially manipulated gene (taken from a naturally occurring gene in other plants) that made them resistant to glyphosate. As a result, when these “Roundup Ready” crops were planted in a field, glyphosate could be used indiscriminately to kill whatever weeds sprouted.

The debate over genetically modified organisms (GMOs) is complex and will not be resolved anytime soon. There have been allegations that GMOs are unsafe, cause genetic anomalies when consumed, or cause cancer. There have also been charges that Monsanto manipulated data and advertising about the safety and efficacy of Roundup and Roundup Ready crops.

Although current science indicates that glyphosate does not cause cancer and Roundup Ready and other GMO crops are safe for consumption, the debate continues in courts and laboratories worldwide.

Health Issues Related to Roundup

Repeated studies by Monsanto, the EPA, and independent labs have failed to find any substantive link between glyphosate and cancer or other health issues. Glyphosate does not appear to build up in human tissues, and there is no evidence that it causes DNA mutation or other cell damage.

More extensive studies carried out by European health agencies and the World Health Organization (WHO) have had mixed results. For example, one study found an increased risk of diffuse large B-cell lymphoma associated with glyphosate while another found that the EPA’s analysis overlooked possible genotoxicity related to Roundup products.

Health Risks Beyond Cancer

Although most cases filed against Monsanto and Bayer have involved cancer, recent research has focused on more subtle injuries that take longer to develop. These issues have only recently come to the attention of the scientific and medical communities, and involve the chemicals in Roundup used to enhance the uptake of glyphosate in plants (known as “inerts” in industry lingo).

Some of these new risks include:

  • Endocrine disruption. The endocrine glands produce hormones related to growth, fertility, and the male and female reproductive systems. Some studies implicate glyphosate in lower fertility and birth rates among women exposed to Roundup.
  • Kidney disease. A study in India suggests that glyphosate may play a role in carrying heavy metals to the kidneys in regions where drinking water is contaminated by pesticide runoff.
  • Microbiome disruption. The role of intestinal microbes is a new area of medical study. It appears that the bacteria living in our guts do more than just digest food and occasionally cause diarrhea. New studies suggest that while humans are not seriously affected by glyphosate, our intestinal flora may be.
  • Neurotoxicity. nationwide study published in 2021 suggests exposure to pesticides, including Roundup, increases the risk of ALS and other progressive neurological diseases.

Although science has not reached any consensus on the hazards of glyphosate, public opinion has swung hard against Roundup. Public opinion has not been improved by Monsanto’s hard stance against transparency in court proceedings and allegations of tampering with regulatory efforts and scientific research.

Difficulties with Establishing Liability

Since the first lawsuit was filed in 2016, claimants, doctors, and legal experts have struggled to make a definitive link between glyphosate and cancer. Despite decades of research and medical cases, establishing a causal link has proven difficult. The cases Bayer has lost have turned on improper labeling, not causation.

What Causes Cancer?

Most cases brought against Monsanto have been claimants with non-Hodgkin’s lymphoma (NHL). This fairly common type of cancer begins in the lymphatic system, the part of the immune system that creates white blood cells. Once cancer begins in the white blood cells, it spreads rapidly throughout the body.

Doctors are not sure what causes NHL. However, some of the risk factors include:

  • Immunosuppressive medications. People who have had organ transplants or take immunosuppressive medication for other conditions are at higher risk for NHL. Medications for rheumatoid arthritis may increase the risk, but the connection is uncertain.
  • Certain bacterial or viral infections. Infections that attack the immune system increase the patient’s risk of developing NHL. HIV, Epstein-Barr, and H. pylori, the bacteria which cause ulcers, can increase the risk of developing lymphoma.
  • Autoimmune diseases. Autoimmune diseases, such as lupus and celiac disease, have been associated with NHL. However, it is unclear whether the medications for these diseases are responsible or whether the diseases themselves increase the risk.
  • Chemical exposure. Insecticides and herbicides have been implicated in NHL. Besides glyphosate, DDT, dioxin, and Agent Orange have similarly been implicated.
  • Other factors. Age, ethnicity, environment, and genetic predisposition may play a role in developing NHL.

There is no single cause of NHL, and doctors are unsure if any one risk factor triggers the onset of lymphoma.

Pinning the Blame on Roundup

For all these reasons, establishing Roundup as the cause of a plaintiff’s illness is extremely difficult. Even if the plaintiffs improperly handled the weed killer for many years, no doctor can say with absolute certainty that it was glyphosate, and only glyphosate, which caused the plaintiffs’ cancer.

In Hardeman v. Monsanto Co., (No. 19-16636 (9th Cir. 2021), the Ninth Circuit declined Monsanto’s request to overturn a lower court verdict in favor of the plaintiff. The plaintiff, Edwin Hardeman, provided exhaustive evidence that Roundup was at least a substantial factor in causing his NHL, and the circuit court agreed. Hardeman was 70 at the time of his cancer diagnosis.

On the other hand, a jury decided that Roundup was probably not at fault for causing the more aggressive form of Burkitt’s lymphoma suffered by a 10-year-old child since the child had only been exposed to the herbicide on one occasion.

Toxic Torts in National Courts

The difference between the results of the two cases above highlights the difficulties of bringing a toxic tort case. Nevertheless, plaintiffs and their attorneys should be prepared to go in with “guns blazing” in a toxic tort case if they want a successful outcome.

Negligence 101

Toxic torts are almost always negligence claims. The plaintiff claims the defendant had a legal duty towards the plaintiff; that duty was breached, and the breach was the proximate cause of the injury.

Duty and breach are usually straightforward in a toxic torts case. We presume that a chemical company has a duty to prevent excessive exposure to harmful chemicals and that it breaches that duty when an individual is exposed due to a company lapse.

Difficulties arise in showing causation and injury.

  • Causation. As shown above, if the science is equivocal about whether a chemical “causes” cancer or any other illness, the plaintiff has a higher hurdle to prove their case. The defendant must work much less to provide evidence that the chemical was not responsible for the plaintiff’s cancer or other illness. In Hardeman, the plaintiff was forced to bring experts to rebut defendant Monsanto’s claims and provide cutting-edge research showing new proof of causality.
  • Injury. Sometimes, the injury is too nebulous to tie to a chemical or cause. One example is the Gulf War Syndrome. This is a cluster of real disorders suffered by veterans of the first Gulf War (Desert Storm) that have never been tied to any known cause. Sarin nerve gas, burn pits, oil well fires, depleted uranium shells, PTSD, and atropine have all been suggested and ruled out. Yet the symptoms persist.

Because of the need for clear causation and definite injury, toxic tort cases like Roundup step outside ordinary negligence claims.

Litigating Negligence Through the Back Door

Cases that have been successful against Monsanto have used state labeling laws, arguing that plaintiffs would have been more cautious or not have used Roundup if the risks had been listed on the packaging. Although juries have found that it is “more likely than not” that Roundup caused the plaintiffs’ cancer, initial cases did not focus on the causation or Monsanto’s negligence in distributing the chemical.

An alternate type of back-door negligence is the “ medical monitoring damages” claim. To date, no medical monitoring damages claims have been filed against Monsanto or Bayer for exposure to Roundup. However, these claims have been successfully brought in toxic landfill cases and other chronic exposure cases where causation is unclear and injury has not emerged.

The advantage of a “medical monitoring” tort is that it reduces the evidentiary burden on the plaintiff. It only requires the plaintiff to show:

  • They were exposed to hazardous substances
  • The defendant was more likely than not the source of the substance or cause of the exposure
  • Long-term medical testing will be required to monitor the plaintiff for potential injury due to exposure

The disadvantage to this monitoring is that recovery is limited to the projected cost of testing unless or until illness develops. However, the recent trend of research on Roundup suggests that this kind of long-term award might be more effective than waiting until the potential plaintiff becomes seriously ill, years or decades following exposure, and then trying to prove causation and negligence.

Current Status of Roundup Lawsuits

The most recent active Bayer case, Langford v. Monsanto Co., settled in California in November 2022 for “an undisclosed amount” (Rumor has it in seven figures). Bayer estimates there are about 30,000 active Roundup cases nationwide.

In July 2022, the Eleventh Circuit ruled that federal law does not preempt state law in state “failure to warn” claims. The Ninth Circuit had previously made a similar ruling, and the Supreme Court denied certiorari in that case.

In January 2023, the entire Eleventh Circuit will make an en banc ruling on Bayer’s claim of federal preemption. It is unlikely they will overturn the original unanimous decision, but this is Bayer’s last hope to prevent other Roundup cases from reaching the court. Even if the preemption argument is granted, it would only affect cases based on failure to warn.

As the Roundup cases continue to move forward and more evidence is uncovered regarding the possible harm caused by glyphosate—in the form of genetic, neurological, and endocrine damage—attorneys should do their best to keep up with trends in both research and court acceptance of medical monitoring as a tort remedy in toxic tort litigation. The number of toxic tort litigants will only increase heading into the new year.


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Morris & Dewett provides this information to the public for general education and interest. The firm does not represent clients in every topic discussed in legal & injury news. The information is curated and produced based on trends in law, governance, and society to present relevant issues to the general public. Every effort is made to provide accurate information. Do not make any decision solely based on the information provided, please seek relevant counsel for each topic area. Consult an attorney before making any legal decision, consult a doctor before making any medical decision, and consult a financial advisor before making any fiscal decision. If you have any legal needs that we can assist you with, please do not hesitate to contact us.

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