The Environmental Protection Agency has decided not to ban the pesticide chlorpyrifos.

The agency’s July 18 decision came the same day as a court-imposed deadline to respond to the merits of a lawsuit from a coalition of environmental and farmworker groups.

“EPA has determined that their objections must be denied because the data available are not sufficiently valid, complete or reliable to meet petitioners’ burden to present evidence demonstrating that the tolerances are not safe,” the agency said in a statement.

Introduced by Dow Chemical (now Corteva Agriscience) in 1965, chlorpyrifos is among the most widely used insecticides for a number of crops including corn, soybeans, broccoli, fruits, and nuts. It is also used at golf courses and other non-agricultural places. Dow voluntarily withdrew the insecticide for household use in 2000.

Lightning Rod

The EPA’s decision to permit continued use of chlorpyrifos will likely land the agency back in court soon.

Chlorpyrifos has become a lightning rod for criticism from public health organizations that point to a number of studies linking early childhood exposure to organophosphates like chlorpyrifos to cognitive delays and alterations of brain structure.

“By allowing chlorpyrifos to stay in our fruits and vegetables, Trump’s EPA is breaking the law and neglecting the overwhelming scientific evidence that this pesticide harms children’s brains,” said Patti Goldman, an attorney with Earthjustice, who served as co-counsel for the petitioners.

The Obama administration proposed in 2015 to revoke all uses of the pesticide. In March 2017, former EPA Administrator Scott Pruitt called for a reassessment .

That June, the League of United Latin American Citizens (LULAC) and other petitioners sued the EPA. They argued that under the Federal Food, Drug, and Cosmetic Act, the EPA is obliged to remove any pesticide from the market if residues of that chemical pose a risk to human health.

The U.S. Circuit Court of Appeals for the Ninth Circuit agreed with the petitioners in August 2018 and ordered the EPA to revoke all food tolerances and cancel all registrations for chlorpyrifos.

But the court in February granted the EPA’s request for a rehearing of the case before the court’s full panel of 11 judges. After the rehearing, the panel directed the EPA to issue “a full and fair decision” on LULAC’s objections within 90 days.

Causes for Concern

Chlorpyrifos was originally developed as an alternative to the pesticide DDT, which itself was a substitute for lead arsenate.

In recent years, researchers at Columbia University found that children who were exposed to chlorpyrifos in the womb exhibited a number of neurodevelopmental problems years after being exposed, such as poorer reflexes, higher risks of attention deficit hyperactivity disorder, or ADHD, and other developmental disorders.

Another team of researchers from University of California, Berkeley, found that 87% of umbilical cord blood samples tested from newborn babies contained detectable levels of the pesticide.

“Scientists have repeatedly made it clear that chlorpyrifos is linked to long-term harm to kids’ brains. But the Trump administration just keeps thumbing its nose at the science,” said Erik Olson, senior director for health and food at the Natural Resources Defense Council.

“Our leaders have a responsibility to protect our most vulnerable residents—our kids—but this administration chooses instead to protect its deep-pocketed allies in the chemical industry,” he said. “Until EPA gets this stuff out of our fields and off our food, this fight is not over.”

In a statement, Corteva said it supports the EPA’s decision, pointing to “more than 4,000 studies and reports examining the product in terms of health, safety and the environment.”

“Completion of Registration Review will provide needed certainty to growers who rely on chlorpyrifos and needed reassurance for the public that labelled uses will not pose unacceptable risk to public health or the environment,” Corteva said.

State Bans

A number of states, including California, Hawaii, and New York have announced plans to either phase out or ban the chemical entirely in the coming years. Canada is currently considering a near-total ban on agricultural uses of chlorpyrifos.

In addition, Sen. Tom Udall (D-N.M.) has sponsored a bill (S. 921) that would ban the chemical nationally. The bill has drawn cosponsors from 13 Democrats and Sen. Bernie Sanders (I-Vt.).

With previous pesticide bans, such as DDT, Earthjustice’s Goldman says the EPA allowed companies every chance to make their own decision to discontinue a problematic pesticide.

“And given the decisions by big agricultural states like California and New York, the writing is now officially on the wall for chlorpyrifos,” she said.

The case is League of United Latin Am. Citizens v. Wheeler, 9th Cir. en banc, 4/19/19.