Chlorpyrifos was first developed in World War II for use in chemical warfare, but has been used for years on crops such as strawberries, oranges, corn and wheat. The EPA banned it for residential use in 2001 and proposed a total ban during President Obama's tenure, but Scott Pruitt, President Trump's first EPA administrator, reversed that order. Pruitt wrote that the science linking chlorpyrifos to neurological effects in children was "unresolved" and that further study was necessary, Green reports.
In the weeks leading up to Pruitt's decision, he secretly promised farm lobbies that he was listening to their concerns, according to internal documents obtained by The New York Times. Pesticide makers also lobbied Interior Secretary David Bernhardt, then the deputy secretary, to block a 2017 study that could have led to tighter restrictions on two pesticides. The Fish and Wildlife Service study found that chlorpyrifos and malathion were so toxic that they threatened the existence of more than 1,200 endangered species.