He has presented hundreds of papers, discussions, and seminars on his research's conclusion that environmental contaminants have played a major role in the global amphibian decline as well as being linked to the many health disparities that occur in minority and low income populations.

There he received his Ph.D. in integrative biology in 1993 for his study of the role that hormone play in mediating developmental responses to environmental changes in amphibians.

[4] After graduating from Harvard University, Hayes worked as a technician and freelance consultant from 1990 to 1992 for Tiburon, California-based Biosystems, Inc.[5] Hayes has held an academic appointment (professorship) at the University of California, Berkeley since completing his doctoral research there in 1992;[3] 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.

His investigations have shown that chemical agents, such as a commonly used herbicide, have the ability to negatively impact the sexual development of the amphibian, even when such toxins are present in low concentrations.

In 1997, the consulting firm EcoRisk, Inc. paid Hayes to join a panel of experts conducting studies for the Swiss pharmaceutical company Novartis (later Syngenta) on the herbicide atrazine.

[10] In 2007, Hayes presented results of his studies to the U.S. National Institute of Environmental Health Sciences showing chemical castration in frogs; individuals of both sexes had developed bisexual reproductive organs.

[11] In 2010, Hayes published research in PNAS[12] describing laboratory work showing how exposure to atrazine turned male tadpoles into females with impaired fertility.

"[15] In 2010, the Australian Pesticides and Veterinary Medicines Authority (APVMA) responded to Hayes' 2010 published paper,[16] by stating that his findings "do not provide sufficient evidence to justify a reconsideration of current regulations which are based on a very extensive dataset.

[6] While a biologist on the Public Broadcasting Service, National Geographic program Strange Days, he expressed his concerns for human health, particularly that of minority and low-paid workers exposure to agricultural chemicals.

[3][24] In 2014, New Yorker writer Rachel Aviv reported that Syngenta might have been orchestrating an attack not only on Hayes' scientific credibility, but on other scientists as well whose studies have shown atrazine to have adverse effects on the environment and/or human and animal health.

[6] Aviv reported that Syngenta had criticized Hayes' science and conduct in press releases, letters to the editor, and through a formal ethics complaint filed at University of California-Berkeley.

[28] Legal counsel from the university responded that Hayes had acknowledged sending letters having "unprofessional and offensive" content, and that he had agreed not to use similar language in future communications.

This talk centered around Hayes' early interest in science - particularly frogs - as well as his career development, research in endocrine disruption, his ongoing feud with Synenta, and the disproportionate way environmentally harmful chemicals affect the lives of minorities and the poor.