The Environmental Protection Agency informed a federal court Aug. 18 that it will ban the pesticide chlorpyrifos, a crop-protection chemical widely used in agriculture for more than 50 years.

The EPA said it could not determine that aggregate exposure to chlorpyrifos meets the safety standards of the Federal Food, Drug and Cosmetic Act. “Accordingly, EPA is revoking all tolerances for chlorpyrifos,” the EPA stated in a rule expected to be published Thursday in the Federal Register.

The ban will become effective in six months.

The decision grants a petition filed in 2007 by two anti-pesticide groups that sought to ban chlorpyrifos. The Obama EPA tentatively proposed a ban, but resisted court pressure to finalize it, leaving the decision the Trump administration.

The Trump EPA denied the petition, but said it would continue to study whether chlorpyrifos meets safety standards.

The 9th U.S. Circuit of Appeals has consistently sided with ban advocates and pushed the Obama and Trump administrations to rule on the petition.

Ban advocates said chlorpyrifos causes brain damage in infants and unborn children. The EPA, under both Obama and Trump, questioned the evidence for that claim.

Household use of chlorpyrifos, unless in child-proof packaging, was banned two decades ago. Farm groups and the Obama USDA defended chlorpyrifos’ use in commercial agriculture as safe and effective.

American Farm Bureau Federation President Zippy Duvall criticized the Biden EPA for departing from how pesticides are reviewed and registered.

“This administration has repeatedly made commitments to abide by science, yet the EPA decision on chlorpyrifos strays from that commitment and takes away an important tool to manage pests and insects,” Duvall said in a statement.

“The integrity of the registration review process and commitment to using sound science must be prioritized in a decision of such far-reaching consequences,” he said.

With the EPA reluctant to declare all uses of chlorpyrifos unsafe, many environmental and labor groups continued to press for a ban through the 9th Circuit. The court in April issued another order to EPA prodding the agency to ban chlorpyrifos.

“Today, we celebrate this huge victory alongside the men and women who harvest our food, who have waited too long for a ban on this pesticide,” United Farm Workers President Teresa Romero said in a statement.