Chlorpyrifos, a potent organophosphate pesticide shown to produce neurologic changes in children has been banned in Europe and California. Registration of the pesticide was due to be withdrawn in the U.S. in 2016 but the EPA failed to respond to a 2007 petition.  The U.S. Court of Appeals for the Ninth Circuit has directed the EPA to either issue a final regulation to modify tolerances for the compound with appropriate safety findings or to revoke registration of chlorpyrifos.  The Court ordered that EPA should respond within 60 days.

The entire subject of regulating chlorpyrifos is moot since Corteva the major manufacturer of the compound has ceased production, based on lack of demand and concern over future litigation.  There is a considerable quantity of chlorpyrifos in inventory and an outright and immediate ban would be beneficial to agricultural workers and their families.