At the end of 1940, a considerable part of Europe had been conquered by Nazi-Germany. As emigration was no longer applied as a means to solve the Jewish question, Eichmann’s Referat within the RSHA was from then on responsible for Jewish affairs and Evictions, in stead of Evictions and Jewish Emigration. Due to a reorganisation, this department was moved to Referat IV B 4. With this office, Eichmann exercised control over all Jews within the Third Reich and he despatched representatives like Alois Brunner, Theodor Dannecker, Dieter Wisliceny and Rolf Günther to the various governments to act as adviser on Jewish affairs. Their task was to promote anti-Jewish policy. His representatives were active in all countries dominated by the Nazis, excepting Scandinavia and the terrritories where the Einsatzgruppen (Special action groups, see Einsatzgruppen Art.) were active.
In the spring of 1941, Special action groups were established in order to eliminate elements hostile to the state in the rear of the German troops who invaded the Soviet Union on June 22nd, 1941. Before extermination camps were equipped to murder Jews, these groups had already murdered more than a million Jews. Executing Jews and clearing away the corpses entailed operational problems. This method was not suitable for efficiently exterminating all European Jews within a short period, which was what Hitler really wanted. So, a definite solution had to be found: the Endlösung.
July 16th, 1941, SS-Sturmbannführer Rolf-Heinz Höppner, chief of the SD in Poznan, Poland wrote to Eichmann: "This winter, there is the danger that not all Jews cannot be fed any longer. Serious consideration should be given to the question whether it would not be the most humane solution to kill those Jews who are not able to work with some sort of fast acting substance. That would be more convenient than letting them starve to death" An increasing number of Nazis was thinking about eliminating the Jews, as already done by the Special action groups and by "natural decline" in the labor and concentration camps and in the ghettos.
July 15th, Heinrich Himmler paid a visit to Hitler in his Wolfsschanze (Wolf’s lair, Hitler’s HQ) in eastern Prussia. Nothing this pair discussed was put down in writing but presumably they had been discussing the fate of the Jews. Eichmann asserted later he was called to Heydrich’s office shortly afterwards. Heydrich would have told Eichmann: "The Führer has ordered to eliminate all Jews" Eichmann later said about this conversation during his interrogations that Heydrich: "contrary to his habit, kept silent for a long time, as if he wanted to see what effect his words had on me". It took a while before Heydrich’s words got through to Eichmann but he stated: "then I understood and said nothing more because there was nothing more to be said". Many historians nowadays contradict Eichmann’s statement and assume that the decision to exterminate all European Jews was only taken in December 1941.
Whatever it was, Eichmann had to draft a document of authorisation which Heydrich presented to Hermann Göring who, as chairman of the Reichsverteidigungsrat was formally still in charge of the policy concerning Jews. The document reads as follows: "In addition to the task, which has been alloted to you on January 24th, 1939, to solve the Jewish question in the best way possible under the present conditions by emigration and evacuation, I hereby order you to make all necessary preparations concerning the administrative, factual and material matters for the final solution of the Jewish question within the German sphere of influence in Europe".
And it goes on: "Furthermore, I order you to send me at short notice an all-encompassing plan concerning the administrative, factual and material matters required for the realisation of the desired Endlösung der Judenfrage (Final solution of the Jewish question)".
Göring signed this document and meanwhile, Himmler had already started on the execution of his plans. He informed the camp commander of Auschwitz, Rudolf Höss, that his camp had been designated to carry out the final solution and that Eichmann would shortly visit the camp to give more details. A few days later, Eichmann paid a visit to Auschwitz and discussed the details of the operation with Höss. They agreed that gassing was the only practical method. A second camp, Auschwitz-Birkenau was to be built with gas chambers to hold 800 persons.
Gassing in extermination camps had to be carried out with carbonmonoxide which was already in use as a means for mass murder. So called gas vans had been in use since 1940 to murder the disabled. An airtight compartment on these trucks was fitted with pipes through which the exhaust fumes were blown in. These trucks were also deployed in Chelmno, the first operational extermination camp. Here Jews were already gassed even before the final solution had been discussed at the Wannsee conference.
In the ghetto in Lodz (at the time named Litzmannstadt by the Germans) in Poland, hundreds of thousands of Jews were packed together. The number of inhabitants had long exceeded its capacity. The Stategovernor of Warthegau, SS-Gruppenführer Arthur Greiser, wanted to get rid of this problem and asked Himmler for help. Himmnler put Heydrich on the case who in turn asked Herbert Lange for his help. Herbert Lange was the commander of Sonderkommando Lange, a unit which had been killing disabled persons since early 1940 in connection with the Tiergartenstrasse 4 (T 4) program of euthanesia. Lange already had experience with the use of gas vans and had to develop their use further as a method for organised murder in Chelmno. Gassing of prisoners was further investigated, also on advise by the chief of the medical branch of the SS, Dr. Ernst von Grawitz. He said poison gas was the most effective and humane way to kill people.
The first group of prisoners arrived in Chelmno on December 7th, 1941 and extermination was begun the next day. The prisoners were told they were to wash themselves but instead of that, they were herded into gas trucks. When the truck was loaded to capacity, the doors were closed and the engine was started. The trucks were driven to a clearing in the woods. When the doors were opened again, the victims should have died. A special clearing squad buried the bodies in a mass grave.
After about 15 minutes, the victims should have died of carbonmonoxide poisoning but Eichmann himself, who had meanwhile been promoted to SS-Obersturmbannführer on November 9th, 1941, discovered that this calculation was not always correct. Ordered by Gestapo chief Heinrich Müller, Eichmann inspected this method of gassing but he was apalled by the poor functioning of it. After 15 minutes, some victims were still alive. In addition, the unloading of the trucks and the burying of the corpses was a depressing task and the vans often broke down on the all but impassable dirt roads. A better method had to be found. Instead of gassing of victims in vans with a capacity of 40 to 50 people, gas chambers of a larger capacity were erected. In the future, all extermination camps would be equipped with gas chambers in which victims were gassed with carbonmonoxide.
A far more efficient method was invented by Rudolf Höss’ deputy, SS-Hauptsturmführer Karl Fritsch. He came up with the idea to use the poison gas Zyklon B instead of carbonmonoxide. This substance was introduced as the standard in the gas chambers of the extermination camps of Auschwitz-Birkenau and Majdanek only at the end of 1942. In some concentration camps, Zyklon B was also used to kill victims. At the end of 1941 however, the majority of Jews was still being killed by shooting or in gas vans. The mass gassing of Jews only got under way in 1942, after the conference at the Wannsee.