Minnesota lawmakers are pushing a proposal to ban chlorpyrifos, a powerful and widely used pesticide that can cause brain damage and developmental defects in children.

The chemical, which is typically sprayed over soybeans, wheat and sugar beets, is the most widely used insecticide in Minnesota. Over the past several years, a growing number of states have banned it over concerns about the harm it can cause both when it is applied and when its residue contaminates food.

The state needs to find better and safer ways to grow crops, said Rep. Todd Lippert, DFL-Northfield, who introduced the proposed ban to a House committee Monday.

"It's unconscionable we're putting our children at risk," he said.

No vote was taken on the ban, which could be included as part of a broader law setting the state's agriculture policies.

Chlorpyrifos has been used since the 1970s. It kills insects that damage more than 50 crops. It's used on about 13% of the state's soybeans and is effective against soybean aphids, a pest that has developed resistance to another common class of pesticides. More than 1 million pounds of chlorpyrifos are sold each year in Minnesota, according to the Minnesota Department of Agriculture.

Exposure to the pesticide can cause memory problems, slow mental processing speeds and lower intelligence in children, said Deborah Bennett, a researcher with the University of California, Davis.

Studies have shown that prenatal exposure increases the risk of attention disorders, she said.

"This is about ensuring that children born in Minnesota have the opportunity to reach their full potential in terms of cognitive ability," Bennett said during the hearing.

Evidence on the pesticide's harm has been clear for more than 20 years, said Emily Marquez, staff scientist at the Pesticide Action Network, a group that has been pushing federal and state regulators to ban chlorpyrifos.

"What exposure really means is disruption of brain development," she said. "The effects will likely last a lifetime. That's too great a consequence for us to ask people to bear in order to keep using this dangerous pesticide."

The U.S. Environmental Protection Agency (EPA) is reviewing federal standards for chlorpyrifos.

The pesticide is safe when it is used as directed under the EPA's guidelines, said Daryn McBeth, on behalf of CropLife America, a trade organization.

"It has stringent label restrictions," McBeth said. "Until the EPA issues its final guidance, growers should be able to use this product."

The pesticide's regulatory status in the U.S. has been uncertain for several years. The EPA banned most indoor uses of it in the early 2000s.

In the final years of the Obama administration, it appeared the EPA was on course to outlaw the insecticide.

But in 2017, the Trump administration reversed course, saying further study was needed. The Biden administration is now taking a fresh look.

In the meantime, California, Oregon, Maryland, Hawaii and the European Union have banned it.

Bonnie Wirtz of Roseville told lawmakers she and her family were living in a small farmhouse in Melrose in 2012 when a plane flew over. It was spraying the neighbor's crops with chlorpyrifos, she said.

The house filled with white mist and she and her infant son had to be rushed to an emergency room, Wirtz said.

"My son had been meeting all of his developmental milestones," she said. But after the home was sprayed, he started falling behind.

He was later diagnosed with an attention disorder and autism.

"Leaving this on the market for one more day is one day too long," she said.

Greg Stanley • 612-673-4882