An independent panel of scientists in California unanimously agreed July 30 that the pesticide chlorpyrifos should be listed as a toxic air contaminant, paving the way for the state to further restrict its commercial use.

The insecticide, which is used on about 60 crops in California, is a developmental neurotoxin especially harmful to young children, according to a draft risk report issued by the state Department of Pesticide Regulation and approved by the state’s Scientific Review Panel on...