"There were no openings in gas chambers II and III through which Zyklon B could be thrown"

The issue of the location of the Zyklon B (hydrogen cyanide) inlets has been raised by Holocaust deniers as key evidence that crematorium basement compartments did not serve as gas chambers.

They claim that the lack of clear traces of inlet openings in the ruins of these buildings proves that the chambers were not used to murder people with Zyklon B.

The facts:

The gas chambers of crematoria II and III had four openings for throwing in Zyklon B pellets. Each opening guided the granules into a vertical wire mesh shaft, which allowed for their even distribution in the chamber. Metal funnels in the shafts further facilitated the distribution and also hastened the vaporisation of the Zyklon B. Thus, the hydrogen cyanide quickly spread throughout the chamber, causing the death of those trapped therein.

These devices were made in the camp metalwork shop based on the design of the Auschwitz SS construction office. The existence of these shafts is confirmed in the crematorium handover document, which mentions their installation.

Excerpt from the testimony of Henryk Tauber from 1945:

‘The gas chamber ceiling was supported by concrete pillars in the centre. There were four shafts to the left and right of these pillars. The outer walls of these shafts were made of a thick wire mesh, running up to the ceiling and outside. Inside this external mesh wall was another finer wire mesh shaft, and inside that a third, yet finer wire mesh chute. Inside the third chute, a container was moved, and powder, from which the gas had evaporated, was extracted from this container with a wire...’

Source: Zeznanie Henryka Taubera, członka Sonderkommando z 1945 roku, [Testimony of former Sonderkommando member Henryk Tauber, 1945], ASMA-B.

A Birkenau crematorium equipment inventory card. It notes the installation of four Drahtnetzeinschiebvorrichtung (wire mesh sliding devices) and four Holzblenden (wooden covers) in the basement chamber of crematorium II. Source: Archives of Auschwitz Museum

The crematorium buildings were blown up by the SS in order to erase all traces of their crimes, which, with the destruction and cracking of the gas chamber ceiling in many places, has to some extent hindered the location of inlet openings. Nevertheless, a thorough inspection of the ruins of the crematoria allows the identification of most of the elements of the gas chambers, including the inlet openings, ventilation ducts and protective grates, and even the imitation showerheads. Their location is also confirmed by detailed studies of the ceilings conducted by Daniel Keren, Harry W. Mazal and Jamie McCarthy. These studies showed the location of the openings, for instance, based on the arrangement of the steel reinforcements in the ceilings. More details on this subject may be found in the report: The Ruins of the Gas Chambers: A Forensic Investigation of Crematoriums at Auschwitz I and Auschwitz-Birkenau.