California is moving ahead with a proposal that could strengthen restrictions on the widely used pesticide chlorpyrifos in the state. Chlorpyrifos is an organophosphate insecticide used to control pests on more than 50 crops, including almonds, grapes, and oranges. The proposed regulation, released on Sept. 19, lists chlorpyrifos as a toxic air contaminant. That means California would regulate the pesticide as an air pollutant that may pose a hazard to human health. Identifying chlorpyrifos as a toxic air contaminant would trigger a risk management process, including a review of emission sources by the California Air Resources Board, to determine if any regulatory action is needed to reduce the risk. The California Department of Pesticide Regulation is accepting comments on the proposal until Nov. 9. The action comes as the U.S. Department of Justice fights to overturn an Aug. 9 federal appeals court ruling that orders the EPA to ban chlorpyrifos nationwide. EPA proposed such a ban under the Obama administration, citing neurodevelopmental risks to children, but the Trump administration put the action on hold for further review until 2022.