This week marks the official end to the Environmental Protection Agency’s approval of genitalia-altering pesticide residues on snap beans. Numerous published studies by an EPA scientist found that rats fed vinclozolin in utero had feminized genitalia with malformations like vaginal pouches, undescended testicles, and malformed penises. Yet the EPA ban did not happen on its own. It took farmworker advocacy and litigation to force EPA to comply with the law and protect people from incredibly nasty chemicals on our food. Here’s how it happened.

In 1997, Erik Nicholson, who worked for Pineros Campesinos Unidos del Noroeste, an Oregon farmworkers union, learned that workers were spraying the pesticide vinclozolin on snap beans grown in the Willamette Valley in Oregon. These beans were grown for local packaging plants that produced frozen green beans.

Historically, the snap beans had been picked by workers. But in the 1970s, Oregon growers shifted to bush snap beans that could be machine harvested. Since the machines can’t distinguish between beans with mold and those without mold, the growers began using fungicides to kill the mold. When the beans became resistant to the first generation of pesticides, the growers looked for a more potent fungicide. Vinclozolin became the pesticide of choice.

But the EPA had not determined that vinclozolin was safe for use on snap beans. In response to growers’ demands, the EPA nonetheless allowed vinclozolin to be used on an emergency basis—not just for just 1–2 years, but 14 years in a row. We went to court to block another emergency approval because EPA regulations restrict emergency approvals to more than 3 successive years. In response, the EPA hastily gave its stamp approval for use of this pesticide on snap beans.

The EPA acted so quickly that it skipped over a crucial step. It had not decided that it would be safe for people to eat beans with residues of vinclozolin. It is illegal for the EPA to allow a pesticide to be sprayed on beans unless it has decided that it is safe to eat beans with these residues. We went to court again and again the EPA responded by rushing through its food safety finding.

The EPA faced a fundamental problem. It had sidestepped the food safety standards that Congress had just enacted in 1996. It had not ensured that the beans would be safe for children to eat under the new standards. Again we challenged EPA’s action.

This challenge became a sparring match with the EPA. Each time we highlighted a shortcoming, the agency would go back and make a new decision dropping vinclozolin uses.

We pointed out that the EPA had not added up all the residues of vinclozolin on snap beans and all of the other fruits and vegetables on which vinclozolin was used. The EPA then added up the residues, found the food risks too high, and canceled some of the uses.

We then challenged EPA’s failure to account for the sexual developments caused to male offspring. The EPA then lowered the allowable residues for other uses. Finally, in 2001, the EPA decided vinclozolin was too harmful to be on our food and it phased out uses on all U.S.-grown food. The ban on food residues on snap beans became effective 10 years ago this week.

This story is proof that citizen oversight is key to enforcing our environmental laws and protecting people from untenable risks. Initially, and throughout the process, the EPA was not inclined to do the right thing. The chemical companies and grower trade groups had EPA’s ear and it repeatedly bent to their will. But when the agency had to defend its action before judges, it realized it had to obey the law.

There is a post-script to this story. Recently, scientific journals found next-generation effects of vinclozolin, meaning sexual behaviors of the offspring of the male rats exposed in utero were impaired. These findings were featured in several articles reporting on this phenomenon of chemical exposure having measurable effects in subsequent generations. We took action to get vinclozolin out of our food based on what we knew in the late 1990s.

It is remarkable that such a well-studied chemical could have such horrific effects that no one suspected at the time. This underscores how important it is for the government to act when there is evidence of harm to people from toxic chemicals.

Earthjustice represented Pineros Campesinos Unidos del Noroeste, the Northwest Coalition for Alternatives to Pesticides, Natural Resources Defense Council, Environmental Working Group in this litigation.