The Nazis developed organophosphates during World War II as nerve gas agents. (Sarin gas is in this family of chemicals.) After the war, the chemical companies adapted the organophosphates to be used as pesticides, primarily as insecticides. Chlorpyrifos is an organophosphate pesticide first registered as an insecticide in the U.S. for both agricultural and residential uses, before Silent Spring and adoption of environmental and health standards in U.S. laws governing pesticide use in 1965.

The pesticide in question, chlorpyrifos, is a nasty piece of work. It’s an organophosphate, a class of bug killers that work by “interrupting the electrochemical processes that nerves use to communicate with muscles and other nerves,” as the Pesticide Encyclopedia puts it. Chlorpyrifos is also an endocrine disrupter, meaning it can cause “adverse developmental, reproductive, neurological, and immune effects,” according to the National Institutes of Health. … More Cabin Crew Survival Guide for dealing with Chlorpyrifos Chemical Exposure