Belzec extermination camp, the model for two others in the Aktion Reinhard murder program, started as a labor camp in April 1940, in the course of the Burggraben-project attached to the Lublin reservation in the same area: the reservation was to serve as a pool for forced labour exploited by various small camps like Belzec, to erect defensive works along the German Nazi-Soviet demarcation line such as a long anti-tank ditch. While the Burggraben project was shut down by the end of the year due to its inefficiency, Belzec was re-opened in 1942 to finish part of the anti-tank ditch.
By 1942, the Nazis had decided to undertake the Final Solution. Operation Reinhard would be the first step in the systematic liquidation of the Jews in Europe; beginning with those within the General Government. Bełżec, Sobibor and Treblinka were created solely to efficiently kill thousands of people. These camps differed from the likes of Auschwitz-Birkenau or Majdanek because these also operated as forced-labour camps.