They say there is now 'sufficient evidence' that children exposed to the insecticides while in the womb can have lower IQs and experience learning difficulties when they reach school-age.
Organophosphates were developed as nerve gases for military use, but are now used to control insects on farms, golf courses, open spaces and parks, and schools.
People can ingest small quantities through food, drinking water and the air they breathe. Although tests have shown that virtually every person in the US has some of the chemicals in their bodies, this can be especially dangerous for pregnant women and the impact on the neurological development of their unborn child, say researchers from the University of California's Davis Environmental Health Sciences Centre.
There have been reductions to the safe levels of organophosphate exposure, but these improvements are not enough to safeguard the health of the unborn child, the researchers say. "It should be no surprise that studies confirm that these chemicals alter brain development since they were originally designed to adversely affect the central nervous system," said Prof Irva Hertz-Picciotto, one of the researchers.
The researchers say that a complete ban is the only safe response but, until that can be implemented, they are calling for all medical staff to be trained in identifying and treating organophosphate poisoning, agricultural workers instructed about safe handling of the chemicals, and less toxic alternatives should be used as soon as possible.
(Source: PLOS Medicine, 2018; 15: e1002671)