Tabun

Tabun is a nerve agent. It was the first of the G-series nerve agents, and called GA. Its potential was known from 
the 1900s because of technical publications.
The substance was developed in 1936 by the German chemist Gerhard Schrader. He was responsible for the I.G. Farben (Leverkusen) work on pesticides. From 1942 Tabun was industrially produced. It was filled in bombs and shells for the Wehrmacht in WWII, but not used.