Atrazine and Frog Reproductive Development
Does atrazine affect frog sexual development? The facts are clear: atrazine does not. Government bodies reviewing the science have concluded that atrazine is safe to use. The EPA and independent researchers around the world have rejected claims made by Dr. Tyrone Hayes about atrazine, noting that his data do not support his conclusions and questioning why he refuses to make his raw data available for independent scientific review.
Scientists and Regulators Question Hayes' Frog Study Data
A careful analysis of Dr. Hayes' March 2010 publication in the Proceedings of the National Academy of Sciences found numerous weaknesses in his methodology and misrepresentations in his citation of data from other studies.

U.S. EPA officials have made it clear that they cannot evaluate Dr. Hayes' studies because he refuses to make his data available. For example, in a letter dated May 17, 2010, Donald Brady, Director of the EPA Environmental Fate and Effects Division, Office of Pesticide Programs, said:
"... I regret that the EPA science staff in the office of Pesticide Program's EFED (Environmental Fate and Effects Division) could not properly account for the sample sizes and study design reportedly used by the Berkeley researchers. As a result, we were unable to complete any independent analysis to support the study's conclusions."
"...no reliable determination of cause-effect or concentration-response relationship could be established between atrazine and reported effects in amphibians."
"EPA presented its review to a FIFRA (Federal Insecticide, Fungicide Rodenticide Act) SAP (Scientific Advisory Panel) and concluded that it was reasonable to reject the hypothesis formulated in 2003 that atrazine exposure can affect gonadal development. The Agency also determined that there was no compelling reason to pursue additional testing with regard to the potential effects of atrazine on amphibian gonadal development."
In testimony before the Agriculture and Rural Development Committee of the Minnesota House of Representatives, Anne Lindsay, former Deputy Director of the EPA, Office of Pesticide Programs, said,
"EPA has taken an especially close look at the research conducted by Dr. Tyrone Hayes which reports that atrazine adversely affects sexual development in frogs, causing a mixture of sex organs in a single animal. EPA has concluded that the existing data are insufficient to demonstrate that atrazine causes such effects. The Agency's conclusions are supported by the independent, expert peer review of the SAP (Science Advisory Panel)."
Global Research Supports Atrazine Safety
A steadily growing body of research conducted by independent labs across the world is showing that atrazine has no negative effect on amphibian development.

A 2008 article in Environmental Science & Technology details the problems researchers have had in trying to replicate any of Dr. Hayes' findings.

A noted South African scientist is quoted in a May 2010 article in Scientific American magazine stating that there is no evidence of problems with African clawed frogs in Africa:
In their native habitats, African clawed frogs do not appear to be suffering from the herbicide. "Atrazine has been used widely in South Africa for the past 45 years, and our studies showed that Xenopus are doing equally fine in agricultural and nonagricultural areas," says zoologist Louis du Preez of North-West University in South Africa. "If atrazine had these adverse effects on Xenopus in the wild, surely we would have picked it up by now."
The Australian government reviewed Dr. Hayes' March 2010 publication, and found that "these papers do not provide sufficient evidence to justify a reconsideration of current regulations which are based on a very extensive dataset."

In an April 2008 story in The New York Times, Yale University scientist Dr. David Skelly found fewer hermaphroditic frogs in agricultural areas where atrazine is used than in suburban areas where it is less likely to be found, saying, "What we found in most of the agricultural ponds we sampled was no evidence of reproductive deformity."