U. California-Berkeley integrative biology professor Tyrone Hayes – whose work includes research on the effects of the herbicide atrazine on amphibian life – has become the target of an ethics complaint from the principal producer of the chemical, Syngenta Corporation.

The complaint, filed July 19, comes in response to a series of “aggressive, unprofessional and insulting, but also salacious and lewd” e-mails written by Hayes to the corporation, according to the complaint.

“so go’head, bring “your boys” / cuz i’m bringing the noise / i told ya, you can’t stop the rage / you been braggin / but we’ll see who’s tea baggin / when TDawg hits the stage,” one e-mail dated March 17 reads.

The e-mail communication had its origins in a scientific disagreement about the safety of the herbicide, which is used to treat crops but is banned in the European Union for the dangers it may pose to human health.

The e-mails, of which there are hundreds, date back to when Hayes published his first studies about atrazine in 2002. Hayes found that frogs exposed to the chemical display female characteristics. Similar experiments on rats, which are genetically similar to humans, resulted in cases of prostate and breast cancer.

Syngenta claims on its website, however, that none of these findings are true. The website states there are “numerous weaknesses in (Hayes’) methodology and misrepresentations in his citation of data from other studies.”

According to Hayes, he was on a Syngenta-sponsored panel of scientists investigating atrazine, but left in November 2000 because he “refused to manipulate data.”

The e-mails reflect some of these scientific disagreements, although Paul Minehart, a Syngenta spokesperson, said they are unprofessional in their approach.

“Our employees find these, at the least, offensive,” Minehart said in an e-mail. “We felt this was contrary to the university’s ethics values and code of conduct, especially regarding ‘respect for others.’ We are hoping that (the complaint) will stop the e-mails.”

Hayes’ e-mails to Syngenta are in rhyme form – a style that he feels is in line with his culture.

“For anyone to tell me that, by virtue of expressing myself in a way that is consistent with my culture, I am unprofessional is offensive,” Hayes said in an e-mail.

This letter of complaint is the second contact Syngenta has made with UC Berkeley officials about the e-mails. The first was in March 2009 and resulted in a meeting between Hayes, former Assistant Vice Provost Nancy Chu and Dean of Biological Sciences Mark Schlissel to discuss the content of the e-mails.

However, another series of e-mails in February provoked a formal letter of complaint – this time addressed to University of California officials. UC Berkeley officials met with Hayes again since the July letter, but decided not to investigate the case further.

“Hayes did not violate any of the faculty code of conduct, so there’s no reason to investigate this,” said Bob Sanders, campus spokesperson. “He has the freedom of the law to say what he wishes.”

Hayes said his e-mails to Syngenta are in response to threats made to him, his family and his graduate students by Syngenta employees.

“(One scientist) has been very offensive and provocative and intimidating,” Hayes said. “He’s harassed me to the point that he’s actually threatened my life and my family blatantly. He and other allies of his have tried to intimidate me through a number of things, such as standing up and disrupting talks, handing out pamphlets at my talks and pulling fire alarms. So I responded.”

Minehart said he could not verify that the interactions occurred.

After a local newspaper, the Peoria Journal Star, published a preview of a talk in March at Illinois State University where Hayes presented his latest research on the “chemical castration” of frogs, three representatives from Syngenta requested a meeting with newspaper officials because they felt their side was not represented in the article.

“Is it unusual for a writer, a scientist and a public relations person to come to a paper to spend a morning to present their perspective? Yes,” said Clare Howard, the journalist who had written the article and was present at the meeting. “It’s very unusual.”

Hayes said he believes that the interactions, as well as the ethics complaint from Syngenta, are methods of intimidation because his research threatens the company’s main product.