Zyklon B
In early 1942, Zyklon B, which contains hydrogen cyanide, emerged as the preferred killing tool of Nazi Germany for use in extermination camps during the Holocaust. The chemical was used to kill roughly one million people in gas chambers installed in extermination camps at Auschwitz-Birkenau, Majdanek, and elsewhere. Most of the people who were killed were Jews, and by far the majority killed using this method died at Auschwitz. Zyklon B was supplied to concentration camps at Mauthausen, Dachau, and Buchenwald by the distributor Heli, and to Auschwitz and Majdanek by Testa. Camps also occasionally bought Zyklon B directly from the manufacturers. Of the 729 tonnes of Zyklon B sold in Germany in 1942–44, 56 tonnes (about eight percent of domestic sales) were sold to concentration camps. Auschwitz received 23.8 tonnes, of which six tonnes were used for fumigation. The remainder was used in the gas chambers or lost to spoilage (the product had a stated shelf life of only three months). Testa conducted fumigations for the Wehrmacht and supplied them with Zyklon B. They also offered courses to the SS in the safe handling and use of the material for fumigation purposes. In April 1941, the German agriculture and interior ministries designated the SS as an authorized applier of the chemical, and thus they were able to use it without any further training or governmental oversight.