Wirth developed his method on the basis of experience he had gained in the fixed gas chambers of Aktion T4. Even though Zyklon B became broadly available later on, Wirth decided against it. Zyklon B was produced by a private firm for both Birkenau, and Majdanek nearby, but their infrastructure differed. 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. For economic and practical reasons, Wirth had almost the same carbon monoxide gas used in T-4, generated with the torque of a large engine. 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. For very small transports of Jews and Gypsies over a short distance, a minimised version of the gas van technology was also used in Bełżec. The T-4 participant and first operator of the gas chambers, SS-Hauptscharführer Lorenz Hackenholt,Michael Tregenza (2000), "The 'Disappearance' of SS-Hauptscharfuhrer Lorenz Hackenholt." A Report on the 1959–63 West German Police Search for Lorenz Hackenholt, the Gas Chamber Expert of the Aktion Reinhard Extermination Camps. Mazel on-line library. Internet Archive. rebuilt an Opel Blitz post-office vehicle with the help of a local craftsman into a small gas van. 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. The guards jokingly referred to the killing site as the Hackenholt Foundation.
Wirth developed his method on the basis of experience he had gained in the fixed gas chambers of Aktion T4. Even though Zyklon B became broadly available later on, Wirth decided against it. Zyklon B was produced by a private firm for both Birkenau, and Majdanek nearby, but their infrastructure differed. 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. For economic and practical reasons, Wirth had almost the same carbon monoxide gas used in T-4, generated with the torque of a large engine. 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. For very small transports of Jews and Gypsies over a short distance, a minimised version of the gas van technology was also used in Bełżec. The T-4 participant and first operator of the gas chambers, SS-Hauptscharführer Lorenz Hackenholt,Michael Tregenza (2000), "The 'Disappearance' of SS-Haup,tscharfuhrer Lorenz Hackenholt." A Report on the 1959–63 West German Police Search for Lorenz Hackenholt, the Gas Chamber Expert of the Aktion Reinhard Extermination Camps. Mazel on-line library. Internet Archive. rebuilt an Opel Blitz post-office vehicle with the help of a local craftsman into a small gas van. 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. The guards jokingly referred to the killing site as the Hackenholt Foundation.