Atrazine: Syngenta's herbicide doesn't just poison frogs - it could give you cancer

Blacks and Hispanics in the US are more likely to get reproductive cancers - could this be the result of Atrazine poisoning? Photo: A Black family picking cotton, 1937. By Louise Boyle via Kheel Center / Flickr.
Blacks and Hispanics in the US are more likely to get reproductive cancers - could this be the result of Atrazine poisoning? Photo: A Black family picking cotton, 1937. By Louise Boyle via Kheel Center / Flickr.

Blacks and Hispanics in the US are twice as likely to get reproductive cancers - caused by Atrazine exposure? Photo: A Black family picking cotton, 1937. By Louise Boyle via Kheel Center / Flickr.

Tyrone Hayes has fought a 15-year battle with Syngenta following his discovery that its herbicide Atrazine scrambles sex in frogs, writes F William Engdahl. Now he wants to know - is Atrazine the cause of the US's 2-fold reproductive cancer excess among Blacks and Hispanics?
Males would develop eggs or ovaries in their testes or essentially turn into hermaphrodites, and later we discovered that sometimes they completely turned into females.

We have already reported on Gottfried Glöckner and the damage that Syngenta GMO maize did to his cows and land, and the shocking details of the tactics the company used to silence him.

This story of a Berkeley University biology professor who conducted independent research on the Syngenta herbicide Atrazine, applied mainly to corn, gives more cause for alarm about the real dangers of patented GMO seeds, and the patented herbicides paired to the seeds.

Banned in the EU to protect groundwater

Atrazine is one of the most widely used herbicides in the USA and Australia. It was banned in the European Union in 2004 because of persistent groundwater contamination.

Even though the US Government continues to allow Atrazine to be used on crops, especially corn and sugarbeets in the United States, the government's own Environmental Protection Agency (EPA) admitted that as of 2001, Atrazine was the most commonly detected pesticide contaminating drinking water in the United States.

Already in 2007 in a report the government agency wrote that "Drinking water from a contaminated groundwater or surface water source can be a significant medium of exposure for children."

A powerful endocrine disruptor

The EPA report also stated: "The primary target of atrazine in humans and animals is the endocrine (hormonal) system. Studies thus far suggest that atrazine is an endocrine disruptor; an agent that has been shown to alter the natural hormonal system in animals.

"Implications of possible endocrine disruption for children's health are related to effects during pregnancy and during sexual development, though few studies are available."

Many of those "few studies available" were done, often without university financial support, because of the persistence of one scientist, Prof. Tyrone Hayes.

He was to be rewarded for his dedication with a 15-year-long campaign to destroy his scientific reputation and worse, from the Atrazine producer, agribusiness GMO and chemical giant Syngenta of Basel, Switzerland.

'They didn't want me to report the data'

Professor Tyrone Hayes was approached in 1988 by Syngenta (then Novartis) to conduct tests on the safety of its Atrazine herbicide. Hayes, despite his young age, was then already one of the world's leading researchers on endocrinology of amphibians such as frogs.

Males would develop eggs or ovaries in their testes or essentially turn into hermaphrodites, and later we discovered that sometimes they completely turned into females.

He was a logical choice. But his research results were hardly what Syngenta wanted. In his experiments exposing African horned frogs (Xenopus laevis) to atrazine, Hayes discovered that atrazine disrupted their sexual development.

That discovery was no small matter, as Atrazine is used on almost half the entire US corn crop and US corn is the largest source of corn used for animal feed in the world, including in the EU.

Hayes ended the relationship in 2001 after Syngenta refused to react responsibly to his alarming findings. 

"Males would develop eggs in their testes or develop ovaries in their testes or essentially turn into hermaphrodites", Hayes said, "and later we discovered that sometimes they completely turned into females."

When he presented his findings to the company, he said, "It became very clear that they wanted me to manipulate data, that they didn't want the science to move forward, that they didn't want me to report the data."

Atrazine's 'likely' role in global amphibian declines

Hayes published his Atrazine work in the Proceedings of the National Academy of Sciences in a devastating paper: 'Atrazine induces complete feminization and chemical castration in male African clawed frogs'. This was a year and a half after quitting the Syngenta panel.

He wrote that what he called "hermaphroditism" was induced in frogs by exposure to Atrazine at levels thirty times below what the EPA permits in water. He hypothesized that the chemical could be a factor in the decline in amphibian populations, a phenomenon observed all over the world.

"Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs.

"Atrazine-exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility.

"These data are consistent with effects of atrazine observed in other vertebrate classes. The present findings exemplify the role that atrazine and other endocrine-disrupting pesticides likely play in global amphibian declines."

'Something very strange is coming up in these animals'

Despite the loss of the Syngenta research contract, Hayes continued studying Atrazine on his own. His further results were more alarming. Hayes repeated the experiments using funds from Berkeley University and the National Science Foundation.

Afterward, he wrote to his research panel, "I feel I should warn you that I think something very strange is coming up in these animals."

After dissecting the frogs - this time wild Leopard frogs (Rana pipiens) in the US, he noticed that some could not be clearly identified as male or female: they had both testes and ovaries. Others had deformed multiple testes.

His results were published in the pretigious journal Nature in his article 'Herbicides: Feminization of male frogs in the wild':

"Here we investigate the effects of exposure to water-borne atrazine contamination on wild leopard frogs (Rana pipiens) in different regions of the United States and find that 10-92% of males show gonadal abnormalities such as retarded development and hermaphroditism.

"These results are supported by laboratory observations, which together highlight concerns over the biological effects of environmental atrazine on amphibians."

The Syngenta attacks begin

Soon he realized he was being followed everywhere by Syngenta representatives, to conferences around the world where he had been invited to speak or attend.

He learned that Syngenta scientists he had earlier collaborated with knew many details about his work and his schedule, and he suspected that they were reading his emails.

In an online Forbes op-ed, Jon Entine, a journalist who is listed in Syngenta's records as a "supportive third party" accused Hayes of being "attached to conspiracy theories", and of leading the "international regulatory community on a wild goose chase", which "borders on criminal."

Documents recently released as a result of a class action lawsuit reveal shocking details of Syngenta's internal war against Hayes. They come from Illinois' Madison County Circuit Court, and were initially sealed as part of a 2004 lawsuit filed by Holiday Shores Sanitary District.

Syngenta's 130-strong secret army

In the emails and other internal Syngenta documents it was revealed that Syngenta officials discussed ways to "discredit Hayes" and "exploit Hayes' faults / problems."

They discussed investigating his wife and doing a psychological profile of him. One suggestion from an April 2005 Syngenta internal meeting was to cut Hayes "in on unlimited research funds", i.e. buy him off.

Another observation made by company officials was that if Tyrone Hayes was "involved in scandal, enviros (environmentalists-w.e.) will drop him."

According to the released documents, Swiss-based Syngenta also routinely paid "third-party allies" to appear to be independent supporters, and kept a list of 130 people and groups it could recruit as experts without disclosing ties to the Syngenta company.

Congenital birth defects and cancers linked to atrazine

Other Atrazine studies inspired by Hayes' earlier results also indicated that atrazine in human studies may harm fetuses and reduce men's sperm quality.

And a paper in Environmental Health Perspectives by mainly Japanese authors, 'Atrazine-Induced Aromatase Expression Is SF-1 Dependent: Implications for Endocrine Disruption in Wildlife and Reproductive Cancers in Humans' (Hayes is the 9th-listed co-author), raised the additional danger of reproductive cancers arising from Atrazine in humans:

"The current findings are consistent with atrazine's endocrine-disrupting effects in fish, amphibians, and reptiles; the induction of mammary and prostate cancer in laboratory rodents; and correlations between atrazine and similar reproductive cancers in humans.

"This study highlights the importance of atrazine as a risk factor in endocrine disruption in wildlife and reproductive cancers in laboratory rodents and humans."

Among the cancers that might be so induced are prostate cancer, breast cancer and testicular cancer and ovarian cancer.

An Indiana University study, independently of Hayes, found that women who lived in areas with higher Atrazine levels in water had children with higher rates of some congenital birth defects. Another 2011 study indicates a link between atrazine exposure and the congenital birth defect gastroschisis, in which the intestine protrudes from the belly wall.

The Holiday Shores case grew into a class action lawsuit that was ultimately settled in 2012 after 8 years of litigation.

While not admitting guilt (corporations never do!), Syngenta agreed to pay $105 million in 2013 toward filtration costs for more than 1,000 community water systems in Illinois, Missouri, Kansas, Indiana, Iowa and Ohio.

EPA concludes - Atrazine is harmless

In 2007, the EPA determined that Atrazine does not affect the sexual development of frogs, a decision again upheld in January 2013 when it wrote:

"EPA concluded that atrazine does not adversely affect amphibian gonadal development. EPA is not currently requiring additional testing of atrazine on amphibians."

By that point, there were 75 published studies on the subject, but the EPA excluded all but 19 of them from consideration, because they "did not meet the requirements for quality" that the agency had set in 2003 - similar to what EFSA claimed in discrediting the Seralini studies on Roundup herbicide and Monsanto maize.

The EPA conclusion was based largely on a set of studies funded by Syngenta and led by Werner Kloas, a professor of endocrinology at Humboldt University, in Berlin.

One of the co-authors was Alan Hosmer, a Syngenta scientist whose job, according to a 2004 performance evaluation, included "atrazine defence" and "influencing EPA."

The threats of scientific corruption

In another paper published in Policy Perspectives, 'Preserving environmental health and scientific credibility', Jason Rohr, an ecologist at the University of South Florida who served on an EPA panel, criticized the "lucrative 'science for hire' industry, where scientists are employed to dispute data."

He wrote that a Syngenta-funded review of the Atrazine literature had arguably misrepresented more than 50 studies and made 144 inaccurate or misleading statements, of which "96.5% appeared to be beneficial for Syngenta."

"Conflicts of interest, situations where personal or organizational considerations have compromised or biased professional judgment and objectivity, can weaken scientific credibility, pose threats to biodiversity and ecosystem services, and are often precursors to corruption."

Atrazine - behind the prostate and breast cancer excess among US Black and Hispanic people?

Hayes is now working on what may prove to be his most explosive research yet - to discover if Atrazine is the cause of the reproductive cancer excess observed among the US's Black and Hispanic minorities. As he writes on his PBS profile,

"In particular, I am concerned about the adverse impacts of Atrazine on endangered species and on racial / ethnic minorities. Prostate and breast cancer are two of the top causes of death in Americans age 25-40, but in particular Black and Hispanic Americans are several times more likely to die from these diseases.

"Ethnic minorities and people of low income are also more likely to hold the 'unskilled' laborer positions in agriculture and pesticide production that would put them at higher risk of exposure and are least likely to have access to the emerging science demonstrating the dangers of exposure.

"Thus, this environmental and public health issue is also a racial / social justice issue because minority and working class people are the primary targets of pesticide exposure."



F William Engdahl is an award-winning geopolitical analyst and strategic risk consultant whose internationally best-selling books have been translated into 13 foreign languages.

He is author of 'Seeds of Destruction: The Hidden Agenda of Genetic Manipulation', and other books. Further information at

Additional reporting by Oliver Tickell.

Also by F William Engdahl on The Ecologist



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