Chemical Weapons were used during WWII... Japan made frequent use of mustard gas and Lewiste against the Chinese. Germany used poison gas to slaughter million

Chemical Weapons were used during WWII... Japan made frequent use of mustard gas and Lewiste against the Chinese. Germany used poison gas to slaughter millions of people in concentration camps. They also used chemical weapons in the Black Sea battles against the Soviets, killing thousands. (The canonical reason given by the OSS for the Nazis not using chemical warfare against U.S. and British forces is that Nazi army logistics in continental Europe relied heavily on horse-drawn transports, and chemical warfare would have inflicted more damage to their own logistical capabilities than to Allied forces.)