Children highly exposed to an insecticide prior to birth showed signs of impaired brain development and motor function, according to a new study of chlorpyrifos " a pesticide still used on US crops despite decades of warnings about its impact on children's health. The study ... is the first to tie prenatal exposure to the pesticide to "enduring and widespread molecular, cellular, and metabolic effects in the brain," the authors wrote. The study ... comes months after the US Environmental Protection Agency (EPA) announced its plans to partially ban chlorpyrifos but allow continued use on 11 crops. The EPA ... banned chlorpyrifos in 2021 after a federal court ordered the agency to take action amid litigation and a wealth of evidence of the risks it poses to children. But the agency reversed course again after a different federal court sided with farm groups in opposition. MRI scans showed that kids with the highest levels of exposure were more likely to have reduced blood flow to the brain, thickening of the brain cortex, abnormal brain pathways, impaired nerve insulation and other problems. Chlorpyrifos was the 11th most frequently found pesticide in food samples in the most recent Food and Drug Administration (FDA) pesticide residue monitoring report, and a 2023 US Department of Agriculture pesticide residue report found traces of the chemical in baby food made with pears, as well as in samples of blackberries, celery and tomatoes.