E.P.A. to Block Pesticide Tied to Neurological Harm in Children

“It is very unusual,” Michal Freedhoff, the E.P.A. assistant administrator for chemical safety and pollution prevention, said of the court’s directive. “It speaks to the impatience and the frustration that the courts and environmental groups and farmworkers have with the agency.”

“The court basically said, ‘Enough is enough,’” Ms. Freedhoff said. “Either tell us that it’s safe, and show your work, and if you can’t, then revoke all tolerances.”

The decision is expected to lead to criticism by the chemical industry and farm lobby, which worked closely with the Trump administration ahead of its decision to keep chlorpyrifos in use.

“The availability of pesticides, like chlorpyrifos, is relied upon by farmers to control a variety of insect pests and by public health officials who work to control deadly and debilitating pests like mosquitoes,” said Chris Novak, the chief executive of CropLife America, an agricultural chemical company, at the time of Trump decision.

Pesticide products that include chlorpyrifos include the brands Hatchet, manufactured by Dow AgroSciences; Eraser, manufactured by Integrated Agribusiness Professionals; and Govern, manufactured by Tenkoz.

Chlorpyrifos will still be permitted for nonfood uses such as on golf courses, turf, utility poles and fence posts as well as in cockroach bait and ant treatments.

In a withering attack on the Trump administration E.P.A., Judge Jed S. Rakoff of the Ninth Circuit wrote on behalf of the court that, rather than ban the pesticide or impose restrictions, the agency “sought to evade, through one delaying tactic after another, its plain statutory duties.”