"Murder was impossible because the doors to the gas chambers were wooden"

One of the arguments of the negationists is that the gas chamber doors would have had to been made of metal to be airtight.

The facts:

Extant evidence indicates that the doors used for clothes disinfection chambers with the application of Zyklon B were made of wood. This proves that wooden doors were sufficiently airtight for the use of Zyklon B whether it be for disinfection purposes or the mass murder of people in gas chambers. There are surviving documents from the SS construction department which refer to the production of gas-tight doors for the Birkenau crematoria. The dimensions of these doors correspond to those of the gas chambers.

A letter from the head of the KL Auschwitz construction department, Karl Bischoff, from late March 1943 concerning the production of a set of gas-tight doors (gasdichte Türen) for the Birkenau gas chambers, then under construction (mentioned here as objects: BW 30 b i BW30c). Source: Archives of Auschwitz Museum.

May 1945. Judge Jan Sehn inspecting a gas-tight door found in the ruins of crematorium V in Birkenau. Source: Archives of Auschwitz Museum

Spring 1945. A gas-tight door dismantled from Birkenau crematorium II, III or IV, in the building materials yard next to the former Auschwitz concentration camp. This type of door was found in all the Birkenau gas chambers. Source: Archives of Auschwitz Museum.

Although made of wood, these doors were solidly built. They included two layers of wooden boards, reinforced with metal fittings, and in between them, there was an insulation layer made of suprema (a mixture of wood shavings and cement). Felt seals lined the door’s edges to ensure gas-tightness. The photograph shows the cross-section of the gas-tight door from crematorium V. Collection of Dr. Igor Bartosik.

The installation of gas-tight doors is confirmed, for instance, in the crematorium inventory lists when they were being transferred to the KL Auschwitz administration. The list below is for part of the crematorium II basement, called the ‘Leichenkeller’ (mortuary), where the installation of a gas-tight door is stated.

The commissioning protocol for Birkenau crematorium II contains a description of the underground chambers. In reference to a chamber called Leichenkeller II (mortuary II), i.e. the gas chamber, mention is made of the installation of a gas-tight door. Source: Archives of Auschwitz Museum.