President Donald Trump's administration denied a petition by environmental groups that sought to ban a common pesticide used on citrus fruits, apples, cherries and other crops, reversing a push by the Obama administration to revoke all uses of the pesticide on food after a government review concluded it could harm children's brains.

In announcing the decision, Environmental Protection Agency Administrator Scott Pruitt said that by not banning chlorpyrifos he is providing "regulatory certainty" to thousands of American farms that rely on the pesticide.

"By reversing the previous administration's steps to ban one of the most widely used pesticides in the world, we are returning to using sound science in decision-making — rather than predetermined results," Pruitt said Wednesday.

Environmental groups pointed to recent studies showing even minuscule amounts of chlorpyrifos, sold by Dow Chemical, can interfere with brain development of fetuses, infants and children. They accused Pruitt of putting the interests of big business over people.

"EPA's refusal to ban this dangerous pesticide is unconscionable," said Patti Goldman, the Earthjustice managing attorney handling the case. "EPA is defying its legal obligation to protect children from unsafe pesticides."

Goldman said her group will seek a court to order to countermand Pruitt's decision.

The pesticide, in use since 1965, has sickened dozens of farmworkers in recent years. Traces have been found in waterways, threatening fish, and experts say overuse could make targeted insects immune to the pesticide.

U.S. farms use more than 6 million pounds of the chemical each year — about 25 percent of it in California.

The EPA banned home use of chlorpyrifos in 2000 and placed "no-spray" buffer zones around sensitive sites, such as schools, in 2012.

But environmental and public health groups said those proposals don't go far enough and filed a federal lawsuit seeking a national ban on the pesticide.

In October 2015, the Obama administration proposed revoking the pesticide's use in response to a petition from the Natural Resources Defense Council and Pesticide Action Network North America.

The EPA said then that its analysis didn't suggest risks from exposure to chlorpyrifos in food. But when those exposures are combined with estimated exposure from drinking water in certain watersheds, "EPA cannot conclude that the risk from aggregate exposure meets the Federal Food, Drug and Cosmetic Act safety standard," it said.

Now under new management, the EPA said Wednesday that the previous administration's proposal relied on a study "whose application is novel and uncertain, to reach its conclusions."

The maker of the pesticide praised Pruitt's decision.

"Dow AgroSciences remains confident that authorized uses of chlorpyrifos products offer wide margins of protection for human health and safety," the company said in a statement.

