When agribusiness giant Sygenta commissioned biologist Tyrone Hayes to study the effects of atrazine, it got more than it bargained for.

A decade ago, Sygenta paid Hayes’ lab at UC-Berkeley $250,000 to study the herbicide’s impact on fish, frogs and reptiles. But Hayes broke ranks after discovering frogs exposed to atrazine developed eggs in their testes and had other serious reproductive abnormalities.

Atrazine is the most heavily used weed-killer in the United States, most often in corn production and forest clear-cutting. It contaminates surface and groundwater, and people with private drinking wells are especially at risk of exposure. While the EPA hasn’t linked atrazine with cancer in humans, Hayes says exposed rats show increased incidences of prostate and breast cancer, and studies suggest the same effect is found in humans.

What are atrazine’s dangers?

In humans, it turns on the gene for a mechanism that’s responsible for turning testosterone into estrogen. Even if we banned it today, data in France suggests it would take more than two decades to get it out of the ground water. We’ve been exposed, our children are exposed, and our grandchildren will be exposed.

The EPA says its job is to weigh economic benefits with adverse health effects. But does it protect human health?

When I think about environmental racism and atrazine, the group getting the economic benefits isn’t the group facing the risks. They are people working in the fields with atrazine levels in their urine 24,000 times higher than levels associated with decreased fertility and feminization of frogs. In large part, they’re the Mexican farm-working community. They don’t have political access and they’re not getting the economic benefit.

In regards to pesticides, the EPA doesn’t have appropriate protective policies. There’s too much influence by those who are wielding the economic benefit side of the equation.

When did you have an epiphany about your role in Sygenta’s studies?

When I took industry funding, I thought, “It’s not my responsibility. You want me to do an experiment. Tell me how you want me to do it. I’ll give you the results and it’s your responsibility to report the results properly.” I naively thought they’d do the right thing. When I saw how they were manipulating the data and the situation and trying to manipulate me, I didn’t want to be a part of what they’re doing to the environment and our health.

Why do we buy into the propaganda that these chemicals are beneficial?

It’s this concept of mastering your universe and controlling your environment. There’s this idea that we’re so advanced that we understand all the consequences.

Did you grow up with pesticides?

I was one of those kids who grew up riding bikes behind the DDT truck.

How do you keep your kids from pesticides?

In our home, we have no pesticides. I think very carefully about what we eat.

How can we protect ourselves?

When I gave public talks, people would say, “You told us what the problems are, but you didn’t tell us what to do.” And I thought, as a scientist it’s not my job. It’s been in the last year I’ve changed my view on that. My advisor used to tell me let the science speak for itself. I realized science isn’t speaking for itself. People on the other side are using science to manipulate people’s opinions. If I didn’t give my expert opinion, I was giving a disservice to the people and country that I care a great deal about.