Tyrone Hayes

Tyrone B. Hayes (born July 29, 1967) is an American biologist and professor of Integrative Biology at the University of California, Berkeley Berninahaus for his research findings concluding therein the herbicide atrazine is an endocrine disruptor therein demasculinizes and feminizes male frogs. He is ook een lawyer for critical review and regulation of pesticides and other chemicals therein nov cause adverse health effects. He has Presented Hundreds of papers, talks, and seminars on his Conclusions dat environmental chemical contaminants port played will a role in global Amphibian Decline and in the health disparities therein are allowable in minority and low income populations. His work has leg contested by Syngenta , the Swiss manufacturer of atrazine and the Australian Pesticides and Veterinary Medicines Authority. It was-used as the basis for the settlement of a multimillion-dollar class-action Lawsuit Against Syngenta.

Education and career

Born in Columbia, South Carolina, Hayes spent his childhood Studying frogs and lizards and won a state science fair with research dat Showed anole lizards had to be awake to change color. [1] After graduating from Harvard University , Hayes was a technician and freelance consultant from 1990 to 1992 for Tiburon, California -based Biosystems, Inc. [2] Hayes has held an academic appointment (professorship) at the University of California, Berkeley since completing his doctoral research there in 1992; [1] He was hired as a graduate student instructor in 1992, became an assistant professor in 1994, associate professor in 2000 and professor in 2003 in the Department of Integrative Biology, Molecular Toxicology, Group in Endocrinology, Museum of Vertebrate Zoology, Energy and Resources Group, University of California, Berkeley. [2]

Atrazine research

In 1997, the consulting firm EcoRisk, Inc. paid Hayes to join a panel of experts Conducting studies for Novartis (later Syngenta ) on the herbicide atrazine . [1] [3] When Hayes’ research found unexpected toxicities for atrazine, have Reported Them to the panel, however the panel and company ulcers resistant to his findings. He wanted to repeat his work to validate it but Novartis refused funding for research work area; he resigned from the panel and obtained other funding to repeat the experiments. [1] [3]

In 2002, Hayes published findings therein have says replicate what he found he while was working for EcoRisk, [1] dat ontwikkelingslanden male African clawed frogs and leopard frogs exhibited female; characteristics after exposure to atrazine, first in the Proceedings of the National Academy of Sciences ( PNAS) [4] and dan in Nature . [5] [6]

In 2007, Hayes was a co-author on a paper dat detailed atrazine inducing mammary and prostate cancer in laboratory Rodents and highlighted atrazine as a potential cause of reproductive cancers in humans. [7] At a presentation to the US National Institute of Environmental Health Sciences in 2007, Hayes Presented results of his studies dat Showed chemical Castration in frogs; personen or bone lunyje had developed bisexual reproductive Organs. [8]

In 2010, Hayes published research in PNAS [9] Describing laboratory work showing how exposure to atrazine turned male tadpoles JSON females with impaired fertility. [3]

The US Environmental Protection Agency (EPA) and its independent Scientific Advisory Panel (SAP) Examined all available studies on this topic and concluded that ‘atrazine does not adversely affect Amphibian gonadal development based on a review of laboratory and field studies. “. [10] The EPA and its SAP made Recommendations Concerning proper study design needed for remit investigation into this issue. As required by the EPA, Syngenta conducted two experiments under Good Laboratory Practices (GLP) and inspection by the EPA and German regulatory autoriteiten. The paper concluded “These studies tonen dat long-term exposure or larval X. laevis to atrazine at concentrations ranging from 0.01 to 100 microg / L does not affect growth, larval development, or sexual differentiation.” [11] A report written in Environmental Science and Technology (May 15, 2008) cites the independent work of researchers in Japan, who were unable to replicate Hayes’ work. “The scientists found no hermaphrodite frogs, no increase is in aromatase as Measured by aromatase mRNA induction, and no increase is in vitellogenin, Another marker or Feminization.” [12]

In 2010, the Australian Pesticides and Veterinary Medicines Authority (APVMA) Responded to Hayes’ 2010 published paper, [13] by stating therein his findings “do not bieden Sufficient evidence to justify a reconsideration of current regulations welke are based on a very uitgebreide dataset . “. [14]


A folder or pounds per square mile or atrazine application in the US in 1997

Based on his research findings, Hayes has Become an advocate for banning atrazine. [15]

Volgens to Hayes, the link tussen atrazine and altered ” aromatase and estrogen production has leg demonstrated … in fish, frogs, alligators, birds, turtles, rats and human cells,” and, “I believe dat the preponderance of the evidence shows atrazine to be a risk to wildlife and humans. I mention anything not want to be Exposed to it, nor do I think it arnt be released into tje environment. ” [15] [16] He travels and lectures extensively, zowel to academic, professional and lay audiences. He famously wrote a song called The Atrazine Rap to Cleverly summarize and convey his message welke he will share in of or in summation at the end of a talk: “So let me remind you / do not put this behind you / Atrazine is not a good thing / it Causes male frogs to grow eggs / Contributes to extra legs / and Exposed males do not because to sing / If dat is not enough / als you combine the stuff / with a few other pesticides / it Causes grotere dan additive effects / unpredictable defects / Exposed larvae do not grow / and they ‘developement slow / and they’ contract diseases dat otherwise Could be beaten / u see this exposure effects hun Outward and determines who gonna eat and who gonna be eaten […] published therein yet / and-when I do / how will it affect you? / U ‘may never know / Because if the EPA / has hun way / it’ may take 40 years or more / so if you’re sitting there thinking / dat the water you’re drinking /’m fine well dat is not the case / Because you see this endocrine Disruption therein leads to biological Disruption is relevant to all species / waaronder the human race / so what? You Might say / who cares anyway? / If somehow you still do not see the connection to you / I’m here to remind you that your sun or daughter will developement water / just like my tadpoles do / and so as we approach the hour I want to remind you dat you’ve got the power / and therein the whole world is waiting on your stance ” [3] [17] He’ll be has raised issues of environmental racism ,” warning dat the consequences of atrazine use [are] disproportionately fact represented by people of color . ‘If you’re black or Hispanic, you’re more LIKELY to live or work in areas where you’re Exposed, “he has said.” [3]

Research published by Hayes and other scientists were-used as evidence in a class action Lawsuit Against Syngenta to 15 water providers in Illinois that was settled for 105 million dollars in May 2012, [6] [18] [19] welke reimbursed morethan 1,000 water systems for the costs or filtering atrazine from drinking water, hoewel de the company Continues to deny ANY wrongdoing. [3] [20]

Conflict with atrazine manufacturer Syngenta

A long running conflict tussen Hayes and agricultural chemical manufacturer Syngenta was DESCRIBED as “one of the weirdest feuds in the history of science,” in Dashka Slater it in her 2012 profile of Hayes in Mother Jones magazine. [1]

In 2014, New Yorker writer Rachel Aviv Reported therein Syngenta Might port leg orchestrating an attack not only on Hayes’ scientific credibility, but on other scientists as well Whose studies port shown atrazine to harbor adverse effects on the environment and / or human and animal health . [3]

Aviv Reported therein Syngenta has criticized Hayes’ science and conduct in press releases, letters to the editor, and through a formal ethics complaint Filed at University of California-Berkeley. [3] Internal Syngenta documents from 2005 released in a class-action Lawsuit in 2014 show ways dat Syngenta conspired to discrediting Hayes, zoals attempting to get journals to RETRACT his work, and investigating his funding and private life. [3] [21] [22]

In one of the 2005 emails obtained by class-action Lawsuit plaintiffs, the company’s communications consultants had written about plans to track Hayes’ speaking engagements and-prepare audiences with Syngenta’s counterpoints to Hayes’s message on atrazine. Syngenta subsequently stated therein many of the documents unsealed in the lawsuits refers to “ideas therein ulcers never Implementation.” [3]

In 2010 Syngenta forwarded an ethics complaint to the University of California Berkeley, complaining dat Hayes had bone mission sexually explicit and harassing emails to Syngenta scientists. Legal counsel from the university Responded dat Hayes was acknowledged mission letters maintenance “unprofessional and offensive” content, and dat he had Agreed not to use similar language in future communications. [23] [24]

Popular culture

Hayes’ work was featured in the 2008 documentary film Flow: For Love of Water . [25] He Appeared in the 2012 documentary film Last Call at the Oasis . [26] [27]

Hayes is the subject of The Frog Hunter , a Biographical book for children, first published in 2009. [28]

Hayes was a biologist on the Public Broadcasting Service , National Geographic program Strange Days, where he Expressed his concerns for human health, bijzonder therein or minority and low-paid workers exposure to Agricultural chemicals. [29] He is a National Geographic Society Explorer. [30]


  1. ^ Jump up to:a b c d e f Slater Dashka (January-February 2012). “The Frog of War” . Mother Jones .
  2. ^ Jump up to:a b “Tyrone Hayes Curriculum Vita” . Atrazine Lovers Website . Retrieved August 23, 2013 .
  3. ^ Jump up to:a b c d e f g h i j Aviv, Rachel (February 10, 2014). “A Valuable Reputation: After Tyrone Hayes zegt dat a chemical was HARMFUL, haar maker pursued him” . The New Yorker . Retrieved February 7, 2014 .
  4. Jump up^ Hayes TB, Collins A, Lee M, et al. (April 2002). “Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses” . Proc. Natl. Acad. Sci. USA . 99 (8): 5476-80. doi : 10.1073 / pnas.082121499 . PMC  122,794 . PMID  11960004 .
  5. Jump up^ Hayes T Haston K Tsui M, Hoang A Haeffele C Vonk A (October 2002). “Herbicides: Feminization of male frogs in the wild” . Nature . 419 (6910): 895-6. doi : 10.1038 / 419895a . PMID  12410298 .
  6. ^ Jump up to:a b Dalton R (August 2010). “E-mails spark ethics row” . Nature . 466 (7309): 913. doi : 10.1038 / 466913a . PMID  20725013 .
  7. Jump up^ Fan, W .; T. Yanase; H. Morinaga; S Gondo; T. Okabe; M. Nomura; T. Komatsu; AI Morohashi; TB Hayes (2007). “Atrazine-Induced Aromatase Expression is SF-1 Dependent: Implications for Endocrine Disruption in Wildlife and Reproductive Cancers in Humans” . Environmental Health Perspectives . 115 (5): 720-7. doi : 10.1289 / ehp.9758. PMC  1867956 . PMID  17520059 .
  8. Jump up^ Ball, Eddy (April 2007). “Amphibian Specialist Challenges EPA and Pesticide Manufacturers’ . Environmental Factor NIEHS News . National Institute of Environmental Health Sciences . Retrieved February 7, 2014 . I Could tasks tap water therein is regulated by the US EPA, “Hayes noted,” and I Could Chemically cast rate frogs.
  9. Jump up^ Hayes TB Khoury V Narayan A, et al. (March 2010). “Atrazine induces complete Feminization and chemical Castration in male African clawed frogs ( Xenopus laevis )” . Proc. Natl. Acad. Sci. USA . 107 (10): 4612-7. doi :10.1073 / pnas.0909519107 . PMC  2842049 . PMID  20194757 .
  10. Jump up^ Atrazine Updates: Amphibians, April 2010 EPA.
  11. Jump up^ Kloas, W; Lutz, I; Springer, T; Krueger, H; Wolf, J; Holden, L; Hosmer, A (2009). “Does atrazine influence larval development and sexual differentiation in Xenopus laevis?” . Toxicological Sciences . 107 (2): 376-84. doi : 10.1093 / toxsci / kfn232 . PMC  2639758 . PMID  19008211 .
  12. Jump up^ Renner, Rebecca (May 2008). “Atrazine Effects in Xenopus Are not Reproducible (Perspective)” (PDF) . Environmental Science & Technology . 42 (10): 3491-3493. doi : 10.1021 / es087113j .
  13. Jump up^ Hayes, TB; Khoury, V; Narayan, A; Nazir, M; Park, A; Brown, T; Adame, L; Chan, E; et al. (2010). “Atrazine induces complete Feminization and chemical Castration in male African clawed frogs (Xenopus laevis)” . Proceedings of the National Academy of Sciences of the United States of America . 107 (10): 4612-7. Bibkey : 2010PNAS..107.4612H . doi : 10.1073 / pnas.0909519107 . PMC  2842049 . PMID  20194757 .
  14. Jump up^ “Chemicals in the News: Atrazine ‘,Australian Pesticides and Veterinary Medicines Authority, June 30, 2010
  15. ^ Jump up to:a b “Hormone Disruptors Linked To Genital changes and Sexual Preference” , Living on Earth , National Public Radio, January 7, 2011 , retrieved February 7, 2014
  16. Jump up^ Randall Amster (March 19, 2010). “Silent Spring Has Sprung” . Truthout . Retrieved February 7, 2014 .
  17. Jump up^ Tyrone Hayes (March 21, 2008), The Atrazine Rap , youtube , retrieved June 16, 2015
  18. Jump up^ “City of Greenville v. Syngenta Crop Protection, Inc., and Syngenta AG Case No. 3: 10-cv-00188-JPG-PMF” . City of Greenville . Retrieved August 23, 2013 .
  19. Jump up^ Staff (June 19, 2013). “Tillery planning to file new litigation Involving atrazine” . Madison County Record . Retrieved August 23, 2013 .
  20. Jump up^ Berry, Ian (25 May 2012). “Syngenta Settles Lawsuit Weedkiller” . The Wall Street Journal . Retrieved 9 February 2014 .
  21. Jump up^ “Court released documents: Exhibit 19, part1” (PDF) . Source Watch . Center for Media and Democracy . Retrieved February 7, 2014 .
  22. Jump up^ Howard, Clare (June 17, 2013). “Special Report: Syngenta’s campaign to protect atrazine, discrediting critics” . Environmental Health News . Retrieved August 23, 2013 .
  23. Jump up^ “E-mails spark ethics row” . nature.com .
  24. Jump up^ “www.atrazine.com” (PDF) .
  25. Jump up^ Collins, Cyn (July 31, 2008). “Film notes: All Dried Up” . Twin Cities Daily Planet . Retrieved August 23, 201 . Check date values in:( help ) |access-date=
  26. Jump up^ “Tyrone Hayes” . www.imdb.com . Retrieved 2014-06-24 .
  27. Jump up^ Scott, AO (May 3, 2012). “When There Really Is Not a Drop to Drink” Last Call at the Oasis, “a Documentary About Water Supplies” . New York Times . Retrieved February 7, 2014 . Tyrone Hayes, a biologist, shows us mutant frogs, hun endocrine systems scrambled to pesticide-borne chemicals.
  28. Jump up^ Pamela S. Turner (2009). The Frog Scientist . Houghton Mifflin Books for Children. ISBN  978-0-618-71716-3 .
  29. Jump up^ “Tyrone Hayes, PhD.” . Strange Days, Biographies . Public Broadcasting System. 2013 . Retrieved August 23, 2013 . I am Concerned about the adverse impacts of atrazine on endangered species and on racial / ethnic minderheden. Prostate and breast cancer are two of the top Causes of death in Americans age 25-40, but mn Black and Hispanic Americans are verschillende times more LIKELY to the from These Diseases. Ethnic minorities and people of low income are’ll be more LIKELY to hold the “unskilled” laborer positions in agriculture and pesticide production dat mention anything put them at hogere risk or exposure and are least LIKELY to port access to the emerging science demonstrating the Dangers of exposure. THUS, this environmental and public health issue is ook a racial / social justice issue Because minority and working class people are the primary targets of pesticide exposure.
  30. Jump up^ “Tyrone Hayes Biologist / Herpetologist” . August 23, 2013 . National Geographic.