Bełżec, in the Lublin province of Poland, was one of the first extermination camps established to carry out the mass murder of Jews during the Holocaust.  Between 430,000 and 600,000 Jews were killed at Bełżec, along with an unknown number of Poles and Gypsies.  Victims were transported to Belzec from Lublin and Lvov, as well as further locations, including Vienna.  Only a few Jews are known to have survived Bełżec. The lack of survivors may be the reason why this camp is so little known despite its number of victims.

Bełżec's three gas chambers began operating officially on March 17, 1942, the date given for the start of Operation Reinhard. Its first victims were Jews deported from Lublin and Lvov. Camouflage was essential to the murder process. A transport numbering 40-60 rail trucks, holding about 2-2,500 Jews, would arrive at Belzec station. It would be divided into two or three smaller convoys that would be pushed into the camp. The Jews would then be rapidly disembarked onto the platform where they were assured that they had arrived at a transit camp. They were told that before being assigned to labor duties elsewhere they would be disinfected and showered. Men were separated from women and children and marched off to large huts where they undressed. Women had their hair shaven off. They were then brutally pushed to "the tube" and into the gas chambers, which were disguised as "showers." The brutalized and disoriented Jews, often weak from hours or days spent in cattle trucks, had barely any time to evaluate their fate or react defensively. 

An eye-witness account of the killing was provided by SS Lt. Kurt Gerstein:

“Unterscharführer Hackenholt was making great efforts to get the engine running. But it doesn't go. Captain Wirth comes up. I can see he is afraid because I am present at a disaster. Yes, I see it all and I wait. My stopwatch showed it all, 50 minutes, 70 minutes, and the diesel did not start. The people wait inside the gas chambers. In vain. They can be heard weeping, "like in the synagogue," says Professor Pfannenstiel, his eyes glued to a window in the wooden door. Furious, Captain Wirth lashes the Ukrainian assisting Hackenholt twelve, thirteen times, in the face. After 2 hours and 49 minutes—the stopwatch recorded it all—the diesel started. Up to that moment, the people shut up in those four crowded chambers were still alive, four times 750 persons in four times 45 cubic meters. Another 25 minutes elapsed. Many were already dead, that could be seen through the small window because an electric lamp inside lit up the chamber for a few moments. After 28 minutes, only a few were still alive. Finally, after 32 minutes, all were dead...Dentists hammered out gold teeth, bridges and crowns. In the midst of them stood Captain Wirth. He was in his element, and showing me a large can full of teeth, he said: "See for yourself the weight of that gold! It's only from yesterday and the day before. You can't imagine what we find every day—dollars, diamonds, gold. You'll see for yourself!"

As Gerstein reported, there were many technical difficulties in this first attempt at mass extermination. The gas chamber mechanisms were problematic and usually only one or two were working at any given time, causing a backlog. Furthermore, the corpses were buried in pits covered with only a narrow layer of earth. The bodies often swelled in the heat as a result of putrefaction and the escape of gases, and the covering of earth split. This latter problem was corrected in other death camps with the introduction of crematoria.

It was soon realized that the original three gas chambers were insufficient for completing the task at hand, especially with the growing number of arrivals from Kraków and Lvov. A new complex with six gas chambers made of concrete, each 4 × 5 or 8 meters, was erected, and the wooden gas chambers were dismantled. The new facility, which could handle over 1,000 victims at a time, was imitated by the other two Operation Reinhard extermination camps: Sobibór and Treblinka. In December 1942, the last shipment of Jews arrived in Bełżec. By that time, the Jews in the area served by Bełżec had been almost entirely murdered, and it was felt that the new facilities under construction at Auschwitz-Birkenau could kill the rest. 

Belzec was built under the direction of Odilo Globocnik, following direct orders on October 13, 1941 from Heinrich Himmler.  Commandants of Belzec included Christian Wirth and Gottlieb Hering, both of whom had previously worked in the Nazi euthanasia program, murdering mentally and physically ill people in Germany.

In 1943, the mass killing of Jews at Belzec was stopped.  Implementing Heinrich Himmler’s secret order to eliminate evidence of the mass murder committed there, the camp was dismantled.  Mass graves were exhumed and corpses burned through the spring of 1943.  By the fall of 1943, the last traces of the death camp were eliminated.