First gassings with cyclon-B

On 3 September 1941, on the orders of camp commandant Rudolf Höß, a group of Soviet prisoners of war and Jews are the first to be gassed in the most gruesome manner with „cyclon-B“ at the recently constructed (1940) concentration camp in Auschwitz (Poland). From now on the hydrogen cyanide based poison gas will be used in all German extermination camps.

Source: shoa.de Tin of Cyclon-B-Gas