When construction began, Birkenau was referred to as a POW camp (Kriegsgefangenenlager), and this terminology continued in use in construction records (correspondence, plans, and reports) until 1944. The location of a camp for Soviet POWs in the vicinity of Auschwitz, and the facts that it was under SS control and that work began on the installation of crematoria with an annual capacity of 525 thousand corpses, indicate beyond any doubt that the intended purpose of the camp was the gradual extermination of the POWs by depriving them of the essential conditions for remaining alive—and this, after all, had been the common practice with regard to POWs since the launching of German aggression against the Soviet Union. This is also confirmed by the fact that over 9 thousand of the 10 thousand POWs imprisoned temporarily in Auschwitz in October 1941 died within 5 months, as a result of the conditions there. All of this was in line with the German exterminationist policy towards Soviet POWs.
In reality, the camp never served its original function. While construction was still underway, in February 1942 at the latest, the Germans decided to change the nature of the camp and make it an integral part of the Auschwitz concentration camp.
This decision would seem to have been made for two reasons. In the first place, the collapse of the German drive on Moscow and the entry into the war of the USA, with its vast economic and military potential, radically altered the German strategic situation in political, economic, and military terms. This situation compelled the leaders of the Third Reich to begin treating the POWs as a labor resource, and to exploit them more widely in German industry. The Birkenau camp did not meet these conditions, since there were no industrial facilities in the Oświęcim area where the POWs could be employed.
Because of this change in policy towards Soviet POWs, the German leadership no longer directed incoming transports from the front to Birkenau, distributing them instead to POW camps and their labor details, such as the POW camp in Cieszyn, which supplied POWs to plants in Upper Silesia.
In the second place, the decision to send mass transports of Jews to the concentration camps in order to exploit them in the German war economy, and the designation of Auschwitz as one of the centers for their extermination as well as a distribution point for Jewish labor resources, meant that quarters had to be prepared in which they could be held temporarily. The Birkenau camp was under construction, and, since it was no longer to be used as a POW camp, this must have seemed like the best solution to the problem.
When the Soviet POWs who remained alive were transferred to Brzezinka in March 1942, the new camp was already a part of Auschwitz Concentration Camp. Instead of POWs, Jews selected for labor were sent there (of the approximately 1.1 million Jews deported to Auschwitz, more than 200 thousand were selected for labor). Some of the 140 thousand Poles registered in Auschwitz, about 23 thousand Gypsies, and men and women from other ethnic groups were also sent there.
The division of Auschwitz into three camps was caused, on the one hand, by the difficulty of administering such an extensive and constantly expanding camp complex; on the other hand, this division formalized the increasingly divergent functions of the entities that made up the Auschwitz complex.
The Auschwitz camp (after the division: Auschwitz I) comprised the central administrative offices as mentioned above, and the main SS warehouses, workshops, and companies: Deutsche Ausrüstungswerke G.m.b.H-DAW, Deutsche Erd-und Steinwerke G.m.b.H – DEST, and Deutsche Lebensmittel GmbH. Working in these units was the principal labor assignment for the prisoners in this camp. On August 22, 1944, there were 15,971 prisoners in this camp (the majority Jewish, although there were 3,934 Poles among them).
The main task of the Auschwitz III camp, made up of sub-camps located at industrial plants, was to rent the labor of prisoners to business concerns.
Auschwitz II, in turn, was above all a center for the extermination of Jews brought there to be killed.
Sick prisoners and those selected for death from the entire complex of Auschwitz camps, and on a vestigial scale from other camps as well, were also assembled and systematically killed in Auschwitz II.
After the implementation of selection of the Jews arriving in mass transports (selection initially took place before deportation, and only later on the unloading ramp in Birkenau), Auschwitz II was intended to become the central labor reservoir and distribution point for the entire concentration camp system, which, in Himmler’s plans, would become involved on a broad scale in the functioning of the German economy. After the rejection of the POW-camp concept, this could serve as justification for building the Birkenau camp on such a gigantic scale. However, Birkenau supplied Germany with prisoner labor on only a very limited scale in 1942-1943. In the first place, the camp’s own labor requirements were great. At this time, as well, concentration camps in Germany proper were placed off limits to Jewish prisoners, who made up an increasing proportion of the Birkenau population; indeed, the transfer of 1,600 prisoners from camps in Germany to Birkenau in October 1942 was the occasion for announcing that German camps were Judenfrei. Such organizational considerations as quarantines, security, and the health situation at Birkenau all served as additional limiting factors.
During this period, in principle, the Germans transferred only Poles to camps in the Reich, in preference to employing them in Silesia, where the chance that they would make contact with local Polish civilians was a political consideration. There were few opportunities for rational employment within Birkenau itself. The camp assigned the greater part of its prisoners to labor in its own sub-camps or in jobs connected with mass extermination: on the unloading ramp or in the gas chambers and crematoria; sorting the baggage plundered from victims; in camp farms; making fuses in the Union armaments factory; or salvaging aircraft wrecks in the Zerlegebetriebe. Half the prisoners were incapable of any sort of work. Only in the spring of 1944 did Germany find itself in such a critical military and economic situation—having lost Byelorussia and the Ukraine, enormous reservoirs of labor—that the leadership abandoned their previous scruples and began transferring prisoners—mostly Jews, but also Poles, Russians, and others—to camps in Germany proper, so that they could be employed in armaments factories.
Once the great transfer of prisoners to camps in Germany began, Birkenau became in effect a transit camp where “human material” went through preliminary selection. People fit for labor and possessing the appropriate qualifications were sent to work in other camps (or put to work in Birkenau itself), while the others, representing superfluous deadweight, were put to death in the gas chambers and burned, or killed through lethal injections, sickness, execution, prolonged roll call, beating by the SS and prisoner functionaries, or hard labor. On August 22, 1944, there were about 90 thousand men and women imprisoned in Birkenau. Sixty thousand of them were registered—designated by camp numbers—and 30 thousand were unregistered. Seventy-four percent of the prisoners in Birkenau at the time were Jews.
Birkenau, like the whole Auschwitz complex, combined two functions in a single place and time: as a concentration camp, that is, a place where various categories of prisoners were imprisoned and slowly exterminated as a result of deliberately created conditions that made long-term survival impossible; and as a direct extermination center, where Jews, above all, were exterminated, although other categories of victims were also murdered on a smaller scale. Prisoners registered in the concentration camp died mainly of starvation; the direct extermination center used the gas chambers above all for this purpose.
Aside from the gas chambers and crematoria, the basic facilities of the extermination center included the unloading ramp and the warehouses used for storing, sorting, and shipping the victims’ plundered property. The basic facilities in the concentration camp were living quarters for the prisoners and the SS supervisors, kitchens, storage areas, workshops, offices, and transportation and communication equipment.
These two constituent institutions that made up the Auschwitz camp complex, which went under the name Konzentrationslager Auschwitz, did not exist in parallel; rather, they functioned in mutual symbiosis. Along with the Security Police posts scattered across the Third Reich and the occupied countries, the extermination center supplied the concentration camp with an uninterrupted flow of human labor; from the concentration camp, it took in corpses and people suffering from terminal exhaustion in order to put them to death and burn them. The concentration camp supplied the direct extermination center with the SS and prisoner crews who worked the unloading ramps, the gas chambers, the crematoria, and the open-air pyres; it also provided the transport that brought the victims and their property to the intended destination, and the clerical services required by the direct extermination center.
Birkenau and the other components of the Auschwitz complex combined in a single place and time the functions of concentration camps like Mauthausen or Dachau with those of direct extermination centers like Treblinka or Bełżec. It represented a new category of Nazi camp, intended to carry out the economic and exterminationist tasks of the Nazi state simultaneously and in the most efficient manner possible.