Belzec was first run by camp commandant Christian Wirth. He was assisted by 20--30 German SS men, and 90--120 Ukrainian guards who volunteered from among the Prisoners of War in the Trawniki camp. Belzec measured 886 feet square and was surrounded by a barbed-wire fence. Watchtowers were situated at the corners of the camp. It was camouflaged so those on the outside could not tell what was going on inside. Belzec was divided into two sections, one in which the Jews were murdered.
In February 1942 the camp's three Gas Chambers were tested on several groups of Jews. On March 17, Belzec officially opened its doors as an extermination center. In its first few weeks of operation, 80,000 Jews were murdered there, over half from Lublin and Lvov. The camp halted operations in mid-April, but began receiving transports again in mid-May, when thousands of Jews arrived from Cracow and the Cracow district.
The Jews were transported by freight trains and traveled for hours or even days under intolerable conditions. Many died on the way. Each train consisted of 40--60 cars. When they arrived at Belzec, 20 cars with more than 2,000 Jews would be detached from the train and pulled into the camp. The Jews were pulled out of the cars, and told that they had arrived in a transit camp, so they were to be disinfected and showered. They were forced to hand over their valuables. Men and women were separated, and all were told to strip. They were marched on the run to the gas chambers by screaming Germans and Ukrainians who beat them along the way. Then they were gassed. At first, this whole process lasted three or four hours, but as the Germans gained more experience, they cut it down to 60--90 minutes.
The Germans, however, were still not satisfied. In mid-June, they halted transports so they could enlarge the gas chambers, in an effort to kill more efficiently. The transports started again in July 1942 and continued arriving regularly until December, when they were stopped because most of the Jews in the Generalgouvernement had already been murdered. During those five months, 130,000 Jews had been brought from the Cracow district, 225,000 from the Lvov area, and many others from the Lublin and Radom districts.
Not all Jews were immediately killed upon arrival: during the camp's first few weeks, some of the strong young men were selected to do Forced Labor. As time went on, 700--1,000 people were kept alive for longer periods so that they could work. One group worked on the trains: they cleaned the freight cars, helped down those Jews who could not disembark on their own, and removed the bodies of Jews who had not survived the trip. Another group worked on the victims' property, making it usable for the Germans. This even included processing women's hair. Another group of several hundred Jews removed the corpses from the gas chambers and buried them in pits. A group of "dentists" was responsible to remove gold teeth from the corpses' mouths. All these laborers were also subjected to brutality and selections from time to time (see also Selektion).
Between late 1942 and spring 1943, the mass graves were opened and the corpses cremated in an effort to conceal evidence of mass extermination. The camp was then closed, and the last 600 prisoners sent to Sobibor. The site was turned into a farm and given to a Ukrainian guard.