[3] It was situated about 500 m (1,600 ft) south of the local railroad station of Bełżec, in the new Lublin District of the General Government territory of German-occupied Poland.

[11] In the territory of the so-called Nisko "reservation", the city of Lublin became the hub of the early Nazi transfer of about 95,000 German, Austrian, and Polish Jews expelled from the West and the General Government area.

[18][19] The "Final Solution" was formulated at the Wannsee Conference in late January 1942 by the leading proponents of gassing (who were unaware of Bełżec's existence),[8] including Wilhelm Dolpheid, Ludwig Losacker, Helmut Tanzmann and Governor Otto Wächter.

[19] Only two months later, on 17 March 1942, the daily gassing operations at Bełżec extermination camp began with the T4 leadership brought in from Germany under the guise of Organisation Todt (OT).

[11][20] The three commandants of the camp including Kriminalpolizei officers SS-Sturmbannführer Christian Wirth and SS-Hauptsturmführer Gottlieb Hering, had been involved in the forced euthanasia program since 1940 in common with almost all of their German staff thereafter.

[19] Wirth had the leading position as the supervisor of six extermination hospitals in the Reich; Hering was the non-medical chief of the Sonnenstein gassing facility in Saxony as well as at the Hadamar Euthanasia Centre.

It was his proposal to use the exhaust gas emitted by the internal-combustion engine of a motorcar as the killing agent instead of the bottled carbon monoxide, because no delivery from outside the camp would be required as in the case of the T-4 method.

However, Wirth decided that the comparable technology of mobile gas vans used at Chełmno extermination camp before December 1941 (and by the Einsatzgruppen in the East),[21] had proven insufficient for the projected number of victims from the Holocaust trains arriving at the new railway approach ramp.

Bełżec was an Operation Reinhard camp meant to circumvent the problems of supply, and instead, rely on a system of extermination based on ordinary and readily available killing agents.

Although Holocaust witnesses' testimonies differ as to the type of fuel, Erich Fuchs' postwar affidavit indicates that most probably it was a petrol engine with a system of pipes delivering exhaust fumes into the gas chambers.

[23] The killing process, using the lethal carbon monoxide, often failed to be completed quickly, inflicting horrific suffering on the victims as they suffocated to death.

They were met by SS-Scharführer Fritz Jirmann (Irmann) standing at the podium with a loudspeaker,[26] and were told by the Sonderkommando men that they had arrived at a transit camp.

[3] The wooden gas chambers—which were built with double walls that were insulated by earth packed between them—were disguised as the shower barracks, so that the victims would not realise the true purpose of the facility.

[28] The workshops for the Jewish prisoners and the barracks for the Ukrainian guards were separated from the "processing" zone behind an embankment of the old Otto Line with the barbed wire on top.

The first phase, from 17 March to the end of June 1942, was marked by the existence of smaller gas chambers housed in barracks constructed of planks and insulated with sand and rubber.

[11] The second phase of extermination began in July 1942, when new gas chambers were built of brick and mortar on a lightweight foundation,[29] thus enabling the facility to "process" Jews of the two largest agglomerations nearby including the Kraków and Lwów Ghettos.

[34] After the war ended, Hering served for a short time as the chief of Criminal Police of Heilbronn in the American zone, and died in autumn 1945 in a hospital.

Of these, just one, Josef Oberhauser (leader of the SS guard platoon), was brought to trial in 1964, and sentenced to four years and six months in prison, of which he served half before being released.

[5][27] Following Operation Barbarossa, all of them underwent special training at the Trawniki SS camp division before they were posted as "Hiwis" (German abbreviation for Hilfswilligen, lit.

[37][38] A detailed description of how the gas chambers at Belzec were managed came in 1945 from Kurt Gerstein, Head of the Technical Disinfection Services who used to deliver Zyklon B to Auschwitz from the company Degesch during the Holocaust.

[30] He witnessed there the unloading of 45 cattle cars crowded with 6,700 Jews deported from the Lwów Ghetto less than a hundred kilometres away,[40] of whom 1,450 were already dead on arrival from suffocation and thirst.

It was the result of direct orders from the Nazi leadership (possibly from Himmler), soon after the Soviet Katyn massacre of 22,000 Polish soldiers was discovered in Russia.

[49] All corpses buried at Bełżec were secretly exhumed and then gradually cremated on long open-air pyres, part of the country-wide plan known as the Sonderaktion 1005.

[3][34] The last train with 300 Jewish Sonderkommando prisoners who performed the clean-up operation departed to Sobibor extermination camp for gassing in late June 1943.

[55] The radio telegram indicated that 434,508 Jews were deported to Bełżec through 31 December 1942 based on numbers shared by the SS with the state-run Deutsche Reichsbahn (DRG).

"[57] The Holocaust train records were notoriously incomplete as revealed by postwar analysis by the Main Commission for the Investigation of German Crimes against the Polish Nation.

Thus, Y. Arad writes, that he had to rely, in part, on Yizkor books of Jewish ghettos, which were not guaranteed to give the exact estimates of the numbers of deportees.

The first monuments were erected, although the area did not correspond to the actual size of the camp during its operation due to lack of proper evidence and modern forensic research.

While Reder submitted a deposition in January 1946 in Kraków, Hirszman was assassinated in March 1946 at his home, by so-called "cursed soldiers", from the anti-communist resistance organisation TOW.

Following the war's end, Hirszman had joined MBP, a secret police organisation created by the new Stalinist regime in Poland, to crush the anti-communist underground.