From the onset, Jewish patients in clinics and sanatoria became euthanasia victims. In Austria, they were concentrated in Vienna's Wagner von Jauregg-Heil- und Pflegeanstalt "Am Steinhof." Viktor Frankl, physician at the Jewish Hospital in Vienna, and Franziska Löw, welfare worker of the Jewish Community of Vienna, tried to save the lives of Jewish patients.
Up to 400 Jews were sent from Steinhof to the extermination center at Hartheim in the course of "Operation T4" in 1940/41, sometimes via intermediary institutions like Niedernhart and Ybbs/Danube. Those who remained at Steinhof and had not perished from malnutrition or infectious diseases, were deported to Terezin, Minsk, or Maly Trostinec by the Central Office for Jewish Emigration in September/October 1942.
In terms of logistics, personnel, and technology, the euthanasia killings represented a crucial first step toward the Holocaust. After the termination of "Operation T4" in mid-1941, the staff of the killing institutions was assigned to "Operation Reinhard," which entailed the murder of the Jews in occupied Poland (General Gouvernement). The former head of security in Hartheim, Christian Wirth, was appointed as commander of the Belzec extermination camp. His deputy in Hartheim, Franz Stangl, assumed command over the Sobibor and Treblinka extermination camps. The experience gained in the industrial extermination of people through "euthanasia" - e.g., the use of stationary gas chambers in centralized killing facilities - was applied in a modified form on a much larger scale.