Killing CentersThe Nazis established killing centers for efficient mass murder. Killing centers were almost exclusively “death factories.” They are also referred to as “extermination camps” or “death camps.” Nazi concentration camps, by contrast, served primarily as detention and labor centers. At the killing centers, Nazi officials employed assembly-line methods to murder Jews and other victims. German SS (Schutzstaffel; Protection Squadrons) and police murdered nearly 2,700,000 Jews in the killing centers by asphyxiation with poisonous gas or by shooting.

Operation T4: The Euthanasia Program 

Killing centers first appeared in Nazi Germany with Operation T4, the "euthanasia" program. The Euthanasia Program was the systematic murder of institutionalized patients with disabilities in Germany. From January 1940 through late August 1941, some 70,273 adult patients were murdered in gas chambers. These gas chambers employed chemically pure carbon monoxide gas.

Chelmno, Belzec, Sobibor, and Treblinka

To carry out the "Final Solution," the Nazis established killing centers in German-annexed and occupied Poland

Established in December 1941, Chelmno was the first killing center for the mass murder of Jews. It was located in the Warthegau, the western part of prewar Poland annexed by Germany during World War II. Mostly Jews, but also Roma (Gypsies), were gassed in mobile gas vans at Chelmno. 

In 1942, Nazi officials established the Belzec, Sobibor, and Treblinka killing centers in the so-called General Government. Between March 1942 and November 1943, the SS and their auxiliaries murdered approximately 1,526,500 Jews in these three camps. The overwhelming majority of Jews deported to Belzec, Sobibor, and Treblinka were murdered in gas chambers immediately upon arrival. These three killing centers were part of Operation Reinhard, the German plan to systematically murder the remaining Jews in German-occupied Poland. In total, 1.7 million victims were killed in Operation Reinhard and related actions.

At the Chelmno and Operation Reinhard camps, victims were killed using carbon monoxide produced by diesel exhaust.


Selection of Hungarian Jews at the Auschwitz-Birkenau killing center.The largest killing center was Auschwitz-Birkenau. By spring 1943, Auschwitz-Birkenau had four gas chambers in operation. Since the Auschwitz main camp (Auschwitz I) was a labor camp, arriving Jewish prisoners faced a selection process. Those judged best able to work were selected for labor. However, the majority of Jews in the transport were sent immediately to the gas chambers. At the height of the deportations, an average of 6,000 Jews were gassed each day at the Auschwitz II (Birkenau) killing center. These gas chambers used the poisonous gas Zyklon B. By November 1944, more than one million Jews and tens of thousands of Roma, Poles, and Soviet prisoners of war were killed there.


Many scholars have traditionally counted the Majdanek camp, which was located just outside the city Lublin, as a sixth killing center. However, recent research has shed more light on the functions and operations at Lublin-Majdanek. 

Within the framework of Operation Reinhard, Majdanek primarily served as a place to concentrate Jews who were spared temporarily for forced labor. Occasionally, especially after Belzec ceased operating in late 1942, Operation Reinhard sent transports of Jews to Majdanek to undergo selection. Jews selected as unfit for labor were murdered either by shooting or in the camp's gas chambers. The Majdanek camp also included a storage depot. There, the Nazis held property and valuables taken from the Jewish victims at the killing centers.

Disguising Mass Murder

The SS considered the killing centers top secret. Sonderkommandos or special prisoner units were deployed to obliterate all traces of gassing operations. These prisoners were forced to remove corpses from the gas chambers and cremate them. The grounds of some killing centers were landscaped or camouflaged to disguise the murder of millions. Moreover, Special Action 1005 (Sonderaktion 1005) began in May 1942. This effort deployed prisoners to exhume and burn bodies from mass graves where cremation was not practiced.