1941 September 3, AUSCHWITZ (Poland)
The first test use of hydrogen cyanide, better known as Zyklon-B gas. The gas was produced in pellets by two companies: Dessauerworks and Kaliworks. The stabilizer for Zyklon-B was made by I.G. Farben. The gas was so lethal that 7.5 gm was enough to kill a 75 kilo person.