Scott Pruitt, head of the Environmental Protection Agency, announced late Wednesday that a widely used pesticide will remain available to farmers, despite agency scientists recommending last year that it be banned due to neurotoxicity risks to farm workers and children.

The pesticide, chlorpyrifos, made by Dow Chemical, is used on tens of thousands of farms in the country to protect dozens of different crops from a variety of insects. However, decades of research following its 1965 debut has found that the pesticide can harm the human respiratory, cardiovascular, and nervous systems. Animal and human studies have linked exposure to declines in learning and memory. When chlorpyrifos was commonly used in household bug sprays, babies exposed prenatally via cord blood showed structural abnormalities in brain regions linked to attention, memory, language, and impulse control.

In 2000, the EPA banned its use from most household products. The agency also began tightening restrictions on its use on farms. In 2007, the Natural Resources Defense Council and Pesticide Action Network North America filed a petition to have chlorpyrifos banned altogether. After more research and some debate from an expert scientific review panel of academic scientists, EPA scientists concluded that chlorpyrifos was causing significant health risks, particularly to farm workers and children, and should be banned.

Nevertheless, Pruitt deemed the scientific findings inconclusive. In a press release, issued late Wednesday, he was quoted as saying:

“We need to provide regulatory certainty to the thousands of American farms that rely on chlorpyrifos, while still protecting human health and the environment. By reversing the previous Administration’s steps to ban one of the most widely used pesticides in the world, we are returning to using sound science in decision-making—rather than predetermined results.”

Sheryl Kunickis, director of the Office of Pest Management Policy at the US Department of Agriculture, praised the decision:

“This is a welcome decision grounded in evidence and science… It means that this important pest management tool will remain available to growers, helping to ensure an abundant and affordable food supply for this nation and the world.”

Environmental groups were quick to condemn the decision, however, as was Jim Jones, a 20-year EPA employee who, for a time, ran the chemical safety unit before leaving upon President Trump’s election. “They are ignoring the science that is pretty solid,” he told The New York Times.

Patti Goldman, an attorney working with the NRDC, told The Times that the organization would pursue a legal challenge. If Pruitt’s decision stands, chlorpyrifos’ safety won’t likely be reviewed again until 2022, when the agency would complete its standard 15-year review process.