Purpose: Effective and harmless pesticide
Result: Gassed millions of Jews to death in the Holocaust
German chemical company Degesch found success in the 1920s by learning how to produce the chemical Zyklon B in canisters. It was effectively used to rid insects from cargo ships. In the United States, small quantities were used to harmlessly delouse the massive influx of immigrants crossing its borders.
All was well until the late 1930s when the SS approached the owner of Degesch and requested he make them a ton of Zyklon B to assist in killing their enemies. He complied, not knowing that the “enemies” were really “millions of innocent elderly people, women, and children.”