Siegfried van den Bergh was an Auschwitz inmate who, right after the war, wrote his war memoirs. Regarding mass murder at Auschwitz, he made the following peculiar claims:
- Poison gas was emitted into the gas chamber through showerheads. However, the product allegedly used at Auschwitz, Zyklon B, contains liquid hydrogen cyanide absorbed on gypsum pellets. The liquid poison evaporates slowly, and the developing gas is not under pressure, hence cannot be ducted through pipework
- The victims allegedly died immediately. However, since the gas evaporated and spread out slowly in the absence of any means to heat and dissipate the toxic fumes, no instant murder would have been possible.
- The gas-chamber floor opened, so that the bodies fell into carts below, which brought them to the cremation furnaces. However, no opening-floor mechanism with carts beneath ever existed at Auschwitz (or anywhere else).
- Flames many meters long came out of the chimneys. However, with the smoke and chimney ducts together almost 30 m long, no flames could have come out of the chimneys.
(For more details, see Mattogno 2021, pp. 295f.)