Illinois is the No. 1 purchaser in the country of an herbicide that may cause breast and prostate cancer, according to Professor Tyrone Hayes from the University of California-Berkeley.

Hayes gave a presentation to the Illinois General Assembly, and later to a community group in Chicago’s Blackstone Library on Feb. 24, about the grave dangers the corn herbicide Atrazine poses to humans and animals. Atrazine is produced by the Swiss company Syngenta. The use of the herbicide is banned in Switzerland and throughout the European Union because of its groundwater contamination.

Hayes’ research is centered on frogs, an animal he said is an important tool for research. If you inject the hormone that initiates human pregnancy into a frog, the frog will lay eggs.

“If you have a compound like Atrazine that’s affecting the hormones of frogs, it will affect human hormones as well,” Hayes said. “Eighty percent of the animals we injected with Atrazine were chemically castrated … that is, animals that were losing their male parts and gaining female parts.”

Atrazine is the best-selling herbicide in the world.

“The chemical is highly mobile, it’s persistent and it’s a known endocrine disruptor,” Hayes said. “There’s a lot of data on humans showing it’s associated with prostate cancer, breast cancer [and] infertility.  And a bunch of studies just came out showing that it causes birth defects and low birth weights.”

Hayes was at the Blackstone Library as an invitee of the Blacks in Greens group, whose president, Naomi Davis, introduced him with an ominous warning about the chemical.

“Peer-reviewed studies from multiple laboratories in multiple countries have shown that Atrazine has adverse side effects even at levels well below the U.S. [Environental Protection Agency’s] drinking water standards,” Davis said.

According to Hayes, the herbicide can travel up to 600 miles in rainwater and can stay in the earth up to 20 years.

“The exposure is primarily through tap water, but it also contaminates groundwater, surface water and rainwater,” Hayes said. “So much so that half million pounds of Atrazine come down in rainfall every year.”

Atrazine has been in use since 1958. It was banned in the European Union in 2004. Last year, Minnesota state Sen. John Marty proposed a ban of the herbicide in Minnesota. His proposal did not make it out of the Senate.

Many of those in attendance for Hayes’ presentation said they hope to see a ban enacted in Illinois.  Two audience members were Environmental Protection Agency officials, who were asked by the agency to attend.

“This is very much an environmental justice issue,” said Cynthia Meyer, an environmental engineer for the EPA. “It affects all of us. It affects humans, it affects animals. It’s pretty scary.”

According to research by Hayes and others, Atrazine causes gender mutations and breast cancer because it creates aromatase in the human body, which turns androgen into estrogen, the main cause of the spread of breast cancer in humans.

Syngenta media relations did not return calls asking for comment.

According to Hayes, the biggest danger is not to the general public, but to those workers who deal with high amounts of Atrazine on a daily basis. Workers in a Syngenta plant in Virginia showed an incredibly high rate of prostate cancer compared to normal rates, Hayes said.  Most of the workers who deal with Atrazine are Mexican migrant workers, and there is no data on how it affects them.

“Over 100 peer reviews published texts show adverse effects of Atrazine on everything from fish to farmers,” Hayes said.