Monsanto’s History: PCBs, Agent Orange, Roundup and the Myths

Few companies have a reputation like Monsanto’s. For many people the name stands for everything wrong with industrial chemicals and agribusiness, and popular online histories describe it as the most evil corporation on Earth. Some of the anger rests on a well-documented record: PCB pollution, Agent Orange, and lawsuits that cost billions. Other parts of the story, such as poisoned bees, aspartame-induced Alzheimer’s or “terminator seeds” forced on farmers, do not survive a look at the evidence. This history keeps the two apart.

From saccharin to PCBs

Monsanto was founded in St. Louis, Missouri, in 1901 by John Francis Queeny and named after his wife’s family. Its first products were food additives, including saccharin, caffeine and vanillin. Over the following decades it grew into one of America’s biggest chemical makers, producing plastics, detergents and industrial chemicals.

The most serious part of its record is polychlorinated biphenyls (PCBs). Monsanto entered PCB production in 1935 by buying the Swann Chemical Company in Anniston, Alabama, and until it stopped in 1977 it was the source of about 99% of the PCBs used by US industry. Congress banned their production in 1979. PCBs are extremely persistent and are linked to cancer and other harm. In 2003 Solutia and Monsanto agreed to pay $700 million to settle claims from more than 20,000 Anniston residents, and as recently as January 2025 Monsanto was ordered to pay $100 million to four people sickened by PCBs at a school in Monroe, Washington (Wikipedia: Monsanto).

In the 1950s Monsanto also sponsored the plastic “House of the Future” at Disneyland’s Tomorrowland, a showcase of its materials:

Agent Orange and dioxin

During the Vietnam War, Monsanto was one of several chemical companies, including Dow, that made the herbicide Agent Orange for the US Department of Defense. Its contamination with dioxin has been linked to serious illness among Vietnamese civilians and US veterans. The Vietnamese government says millions of people were exposed; the US government has disputed some of those figures, and exact death tolls are not established (Wikipedia: Agent Orange).

US veterans sued the manufacturers. Their main class action did not end with the case being thrown out, as the popular story says: in May 1984, just before jury selection, seven manufacturers settled for $180 million, and Monsanto was ordered to pay slightly over 45% of it.

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Aspartame, saccharin and rBGH: what the science says

Monsanto bought G.D. Searle, the maker of aspartame (NutraSweet), in 1985, after the sweetener had already been approved. Claims that aspartame causes Alzheimer’s disease, is “more addictive than crack” or produces dozens of listed diseases are not supported by evidence. In 2023 the WHO’s cancer agency classed aspartame as “possibly carcinogenic” (Group 2B) on limited evidence, while the joint FAO/WHO expert committee kept the acceptable daily intake at 40 mg per kg of body weight; a 70 kg adult would need to drink more than 9 to 14 cans of diet soda a day to exceed it (WHO, July 2023).

Saccharin was listed as a possible carcinogen in 1981 after bladder tumours in rats given high doses, but it was removed from the US list in 2000 because the rat mechanism does not apply to humans (National Cancer Institute). Monsanto’s recombinant bovine growth hormone, sold as Posilac from 1994, was controversial and is not approved in the EU or Canada; the company sold the business to Eli Lilly in 2008.

(The video originally embedded here is no longer available on YouTube.)

(The video originally embedded here is no longer available on YouTube.)

GM seeds, patents and farmers

From the mid-1990s Monsanto turned into a seed and biotechnology company, selling crops engineered to tolerate its Roundup herbicide or to resist insects. Here the record and the myths diverge most:

• Safety. A 2016 review by the US National Academies found no substantiated evidence that commercial GM crops are less safe to eat than conventional ones. It did find a real problem: weeds that have evolved resistance to glyphosate (National Academies, 2016).
• “Terminator seeds”. Seed-sterility technology was patented, but Monsanto’s chief executive pledged in 1999 not to commercialise it (ETC Group), and no such seeds have been sold.
• Patents and lawsuits. Monsanto did sue farmers who replanted its patented seeds. In Bowman v. Monsanto (2013) the US Supreme Court ruled unanimously that buying seed does not give a farmer the right to multiply it by replanting (Wikipedia: Bowman v. Monsanto). The court cases involved deliberate replanting, not seeds blown onto organic farms.
• Farmer suicides in India. A review of the evidence found no “resurgence” of suicides caused by Bt cotton, though in some districts and years crop failures and debt contributed to farmers’ distress (Gruère and Sengupta, Journal of Development Studies, 2011).

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Roundup and glyphosate in court

The biggest modern controversy is glyphosate, the active ingredient in Roundup. In 2015 the WHO’s cancer agency classed it as “probably carcinogenic to humans”; the US Environmental Protection Agency has long considered it unlikely to cause cancer. Tens of thousands of people who developed non-Hodgkin lymphoma sued. In 2020 Bayer agreed to pay roughly $8.8 to $9.6 billion to settle around 100,000 claims, plus money for future cases.

Questions about the science have continued. In November 2025 a journal retracted a 2000 review of glyphosate’s safety after it emerged that Monsanto staff had helped write it without disclosure (Wikipedia: Monsanto). Then on 25 June 2026 the US Supreme Court ruled 7–2 in the Durnell case that federal pesticide law pre-empts state failure-to-warn claims where the EPA has not required a cancer warning. The ruling was about labelling, not about whether glyphosate causes cancer (KBIA / Missouri News Network).

Bees, bans and other claims that don’t hold up

• Bees. GM crops are not engineered to kill bees. A 2013 USDA and EPA report found no single cause of colony losses and named the varroa mite as the major factor, along with disease, poor nutrition, genetics and pesticide exposure (Farm and Dairy on the USDA/EPA report).
• “Banned everywhere”. Many countries restrict GM cultivation, and the EU requires approval and labelling, but GM products are imported and used across Europe. No country has convicted Monsanto of “crimes against humanity”.
• The “Monsanto Protection Act”. This was a temporary rider in a 2013 US spending bill that let farmers keep growing approved GM crops while court challenges proceeded. It was not renewed and lapsed later that year.
• Numerology. Claims that the name adds up to 666 tell us nothing about the company.

Monsanto today

Bayer agreed to buy Monsanto in 2016 and completed the deal on 7 June 2018, after which it dropped the Monsanto name while keeping its product brands. The legacy has not gone away: PCB cases continue, the glyphosate litigation has reshaped Bayer’s finances, and in 2026 a BBC One programme featuring Michael Sheen, Buried, revisited Monsanto’s PCB dumping in Wales.

The documented history is serious enough without exaggeration. If you want to make your own choices about food and farming, the most useful tools are reliable sources, honest labelling and a clear sense of which risks are real. Our list of GMO products and companies is one place to start.

Sources: Wikipedia: Monsanto; Wikipedia: Agent Orange; WHO, 14 July 2023; NCI: Artificial sweeteners and cancer; National Academies, 17 May 2016; ETC Group: Monsanto’s 1999 terminator pledge; Bowman v. Monsanto Co.; Gruère and Sengupta (2011); Farm and Dairy, May 2013; KBIA, 25 June 2026.

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