In German-occupied Europe during World War II, the killing center was a facility established exclusively or primarily for the assembly-line style mass murder of human beings. Those few prisoners who were selected to survive, temporarily, were deployed in some fashion in support of this primary function. The killing centers are sometimes referred to as "extermination camps" or "death camps."

Concentration camps served primarily as detention and labor centers, as well as sites for the murder of smaller, targeted groups of individuals. Killing centers, on the other hand, were essentially "death factories." German SS and police murdered nearly 2,700,000 Jews in the killing centers either by asphyxiation with poison gas or by shooting.


ChelmnoChelmno was the first killing facility to begin operations, in December 1941. It was located in the Reich province Wartheland, which encompassed a part of Poland annexed to Germany. At Chelmno, a former aristocratic manor house served as the reception area. Members of a special detachment of SS and police subordinate to the Higher SS and Police Leader for Wartheland guarded the facility and killed people in trucks, in which the exhaust pipes had been reconfigured to pump carbon monoxide gas into sealed paneled spaces behind the cabs of the vehicles. The bodies were then driven into a nearby forest, where mass graves had been dug. The Germans killed at least 172,000 people at Chelmno between December 1941 and March 1943 and then again in June and July 1944. Almost all of the victims were Jews, but there were also approximately 4,300 Roma (Gypsies) victims, as well as an undetermined number of Poles and Soviet prisoners-of-war.

Operation Reinhard

Rozia GrynbaumOperation Reinhard (Einsatz Reinhard) became the code name for the German plan to systematically murder the approximately two million Jews residing in the so-called General Government.

To implement “Operation Reinhard,” the SS and police constructed three killing centers: Belzec, Sobibor, and Treblinka. The Belzec and Sobibor killing centers were located in Lublin District. The Treblinka killing center was located in Warsaw District. All three Operation Reinhard killing centers were managed by SS and police officials assigned to the staff of the Lublin SS and Police Leader. In addition, specially trained police auxiliaries guarded these camps and facilitated the murder operations conducted there. These auxiliaries trained at the Trawniki training camp, a special camp located in Lublin District.

Belzec began operations in March 1942, concurrent with the deportations of the Jews from Lublin and Lwów (L'viv). Sobibor began its operations in May 1942, with the deportation of Lublin District Jews from rural regions. Treblinka II began operations in July 1942, concurrent with the major deportation of Warsaw Jews in summer 1942.

The victims of the Operation Reinhard killing centers included Polish, German, Austrian, Dutch, French, Czech, and Slovak Jews as well as Roma (Gypsies), Soviet prisoners of war, and Poles. The SS and police killed the majority of prisoners deported to the Operation Reinhard killing centers by locking them in stationary gas chambers into which truck engines pumped deadly carbon monoxide gas. A minority of prisoners were killed by shooting.

Small numbers of prisoners were selected from each transport to support the main function of the camps: the killing of human beings. Members of these detachments, often called Arbeitsjuden (“work Jews”) and sometimes collectively referred to as a Sonderkommando (Special Detachment), worked in the killing area. They removed bodies from the gas chambers and initially buried them in mass graves. In late 1942 and 1943, the Jewish forced laborers had to exhume the buried bodies and burn them in huge trenches on makeshift “ovens” made of rail track.

Other prisoners selected for temporary survival worked in the administration-reception area, facilitating detraining, disrobing, relinquishment of valuables, and movement of new arrivals into the gas chambers. They also sorted the possessions of the murdered victims in preparation for transport to Germany, and were responsible for cleaning out freight cars for the next deportation. German SS and police personnel and the Trawniki-trained auxiliaries periodically murdered the members of these detachments of Jewish laborers, and replaced them with persons selected from newly arriving transports.

In the Operation Reinhard killing centers, the SS and their auxiliaries killed approximately 1,526,500 Jews between March 1942 and November 1943. In total, the SS and their auxiliaries murdered 1.7 million Jews killed in Operation Reinhard killing centers and related actions.

Approximately 300 prisoners survived the three camps. Almost all of those who survived did so by escaping Treblinka or Sobibor killing centers during uprisings in August and October 1943, respectively.

Belzec ceased operations in December 1942. Sobibor and Treblinka closed down in November 1943.


The largest killing center was Auschwitz-Birkenau, also known as Auschwitz II. It was located in Upper Silesia, a province of interwar Poland that was annexed directly to Germany. SS authorities established Auschwitz-Birkenau in the spring of 1942.

Unlike Chelmno and the Operation Reinhard killing centers, the Auschwitz concentration camp complex was not subordinated to the regional SS and police leader, but was part of the concentration camp system under the SS Economic-Administration Main Office. Auschwitz-Birkenau was originally designated as a forced-labor camp for large numbers of, initially, Soviet prisoners of war and, later, Jewish forced laborers to be deployed on SS-inspired construction projects. Auschwitz-Birkenau developed into a killing center in the first weeks of its existence. From the first transports of Slovak Jews in spring 1942, the SS established a practice of selections, in which those arriving Jews who were unable to work were sent directly to two makeshift gas chambers.

During spring 1942, in the wake of the Wannsee Conference, Himmler and the RSHA designated Auschwitz-Birkenau as the “final” destination for the European Jews (excepting the Jews of Wartheland Province, the Generalgouvernement, and the occupied Soviet Union). In response, SS authorities constructed four enlarged and “improved” gas chambers in Auschwitz-Birkenau; these were completed in early 1943. Like other concentration camps but in contrast to other killing centers, the SS used Zyklon B gas (prussic acid) in the gas chambers at Auschwitz-Birkenau.

Auschwitz: Oral History Excerpts

During the deportation of Hungarian Jews in the spring of 1944, Auschwitz-Birkenau reached peak killing capacity: the SS gassed as many as 6,000 Jews each day. By November 1944, the SS had killed more than a million Jews and tens of thousands of Roma, Poles, and Soviet prisoners of war in Auschwitz-Birkenau. At least 865,000 Jews were killed immediately upon arrival. The overwhelming majority were killed in the gas chambers.

Unlike Chelmno and the Operation Reinhard killing centers, Auschwitz-Birkenau also functioned as a forced-labor camp and as a holding pen for groups of Jewish and Romani (Gypsy) families. Indeed, the facility never lost its original function as a forced-labor camp, though its primary function became mass murder in 1942. In 1944, the SS liquidated the inhabitants of the Jewish family camp, virtually all of whom had been deported to Auschwitz-Birkenau from Theresienstadt. The SS also liquidated the inhabitants of the Gypsy family camp, families deported from Germany, Austria, and the Czech lands. In these operations, nearly 10,800 Jews and nearly 2,900 Roma were killed in the gas chambers.

The Operation Reinhard Camps and Chelmno were dismantled after their murderous work was done. Auschwitz-Birkenau, on the other hand, continued to serve as a concentration camp for forced laborers after the destruction of the gas chambers in November 1944. Most of the prisoners, however, had been evacuated by foot or on trains prior to the liberation of the camp by units of the Soviet Army on January 27, 1945.


Soviet prisoners of war arrive at the Majdanek camp.Though many scholars have traditionally counted the concentration camp Lublin, located near the Majdan suburb of Lublin in the Generalgouvernement and often known as “Majdanek” (little Majdan), as a sixth killing center, recent research had shed more light on the functions and operations at Lublin/Majdanek. Like Auschwitz-Birkenau and unlike Chelmno and the Operation Reinhard killing centers, Lublin/Majdanek was designated to be a large-scale forced-labor camp, initially for Soviet prisoners of war and, later, for Jews. At the time the SS established it in November 1941, the camp had the designation “Prisoner of War Camp of the Waffen SS Lublin” and was subordinated to the SS and police leader in Lublin District. Later it became a part of the concentration camp system.

Unlike Auschwitz, Lublin/Majdanek never lost its primary function as a forced-labor and concentration camp. In November and December 1942, 24,000 Jews arrived there who would have been destined for the Belzec killing center, had the Germans not decided in October to shut Belzec down. However, the majority of Jews deported to Majdanek had been pre-selected as potential forced laborers during ghetto operations, at the railroad station in Lublin, or even in the Sobibor and Treblinka killing centers themselves.

While the camp was under construction from November 1941 until the late spring of 1943, the general living conditions in Lublin/Majdanek were appalling, resulting directly in the death of the majority of its prisoners or weakening them sufficiently that the SS then killed them in the gas chamber because they were incapable of work.

Recent research has revealed that no more (and possibly fewer) than 170,000 prisoners passed through the main camp at Lublin/Majdanek, nearly half of whom were Jews and most of the rest Poles, Soviet prisoners of war, Soviet civilians, and Czechs. As many as 80,000-90,000 of the prisoners were Jews. The SS killed 60,000-72,000 of the Jews, though less than half were killed upon arrival and not all of these victims were killed in the gas chambers. The majority of the Jewish victims at Lublin/Majdanek died as a result of brutal conditions or mistreatment or were sent to the gas chambers in small groups only after being registered in the camp and then being deemed incapable of work. Perhaps as many as 20,000 were shot weeks or months after their arrival in the camp, including the last 18,000 Jewish prisoners, who were shot on November 3, 1943 as part of Operation “Harvest Festival” (Unternehmen Aktion Erntefest) in ditches dug just outside the camp.

Between March 1942 and November 1943, Jewish prisoners made up the majority—at times the overwhelming majority—of prisoners at the Lublin/Majdanek concentration camp. After the “Harvest Festival” murders in November 1943, Jews made up the smallest percentage of prisoners in Majdanek (357 out of 6,565 in December 1943, 5.44%). The SS evacuated virtually all of the surviving prisoners from Majdanek to other concentration camps further west between April and July 1944, leaving only a few hundred prisoners to be liberated by Soviet troops on July 23-24, 1944.

Secrecy Surrounding the Killing Centers

The SS considered the operations of the killing centers to be top secret, classified information. As with other aspects of the "Final Solution of the Jewish Question" as well as with all matters related to operations of SS-run camps, the perpetrators were sworn to secrecy and could face prosecution in the event of unauthorized disclosure of information.In part to uphold this secrecy and in part due to health and space reasons, the SS leadership ordered the camp authorities in the autumn of 1942 to henceforth burn the bodies of those murdered at the killing centers and to exhume the bodies of those already buried in order to burn them. At the Operation Reinhard killing centers and Chelmno, the corpses were burned on “open air ovens” made of rail track. Special detachments of Jewish forced laborers were brought in from outside to perform this grisly task at Belzec and Chelmno and to complete it after the Treblinka II and Sobibor uprisings. After the job was done, the members of these detachments were shot by the SS or their Trawniki-trained auxiliaries. At Auschwitz-Birkenau, large crematoria were built with the new gas chambers in 1942-1943. Detachments of Jewish laborers, known as Special Detachments (Sonderkommando) and made up of persons selected from incoming transports disposed of the corpses until the gassing operations ceased in November 1944.

The Operation Reinhard killing centers were completely dismantled and the land was re-landscaped to camouflage the sites as agricultural estates. At the first killing center, Chelmno, camp officials dismantled the camp and destroyed the so-called manor house before abandoning the site in April 1943. The site was used again as a gassing site briefly between late spring and summer of 1944, primarily for the Jews of the Lodz ghetto. SS demolition experts likewise destroyed the gas chambers at Auschwitz-Birkenau following the last gassings, in November 1944, but the camp continued to function as a concentration camp until the arrival of Soviet troops on January 27, 1945.