Chlorpyrifos is an organophosphate insecticide. It has been banned for residential use since 2001 because of the heath risks it presents for children. But the pesticide's residue is still persistent in the environment. In addition, it is still sprayed commercially on some agricultural crops, including fruit trees and vegetables, and is also used on golf courses and for mosquito control. However in August 2018, a federal judge ordered the Environmental Protection Agency "to revoke all tolerances and cancel all registrations for chlorpyrifos within 60 days." The EPA is reviewing the decision.

It's not the first time the insecticide has come under scrutiny. A 2012 study regarding the widely used pesticide, chlorpyrifos, shows a link between exposure and its effect on kids' brains — particularly for boys.

The study, published in the journal Neurotoxicology and Teratology and reported on by Environmental Health News followed 335 pairs of mothers and children that were part of a large group of families living in low-income neighborhoods in New York City that have been tracked by Columbia University scientists since the kids were born. Several years ago, researchers were able to test each child's umbilical cord blood after birth to determine exposure level to various chemicals — including chlorpyrifos. Now, as many of the children are reaching school age, researchers are able to link the effect of various levels of chlorpyrifos exposure with each child's short-term memory.

For the boys, prenatal exposure to chlorpyrifos was associated with lower scores on short-term memory tests than girls who were exposed to similar levels of the pesticide. Scores were an average of three-points lower for boys than girls. These findings suggest that chlorpyrifos may harm boys’ developing brains more than girls’.

Editor's note: This article has been updated since it was originally published in August 2012.

What you need to know about chlorpyrifos
This pesticide used in farming can affect boys' short-term memory.