Wednesday, May 16, 2012

Review of the Debate on the Gas Openings at Crematoria 2 and 3 in Auschwitz - Part I: Evidence

The issue of gas introduction openings in the basements of crematoria 2 and 3 in Auschwitz-Birkenau will be dealt with in three postings; this first presents the various pieces of evidence, the second is discussing the most common Revisionist arguments, and the last is concluding some final remarks.  

Part I: Evidence

Part II: Revisionist arguments

Part III: How it sums up

Testimonial evidence

28 affirmative accounts on the gas openings in crematorium 2 and 3 are compiled here (for a summary table see here).

It is first of all striking that the accounts are not limited to a specific group and certain occasion, but are distributed among several groups of people involved in the concentration camp – SS personnel, Jewish prisoners, Polish prisoners, Soviet prisoners, civilians – and were given at numerous different circumstances – Soviet/Polish investigations, British investigations, Allied investigations, West-German investigations, in a letter to historian, interviews with a historian, interview with a Revisionist, contemporary reports, drawings, books. The heterogeneous nature of the accounts is remarkable and already indicates that there is something to it.

Numbers of openings

11 accounts have identified four gas openings. 

2 accounts have identified three or four openings.

3 accounts have mentioned two openings. According to testimonial evidence (Henryk Tauber, Yehuda Bacon, Paul Bendel, Daniel Bennahmias, Josef Sackar), the gassing basement(s) was (were) later subdivided into two separate chambers in order handle smaller transports more easily. Each chamber was then equipped with two gas openings. The references to two gas openings can be interpreted in the context of the subdivision and are thus in principle compatible with a total number of openings of four for the whole basement. In total, these are 13 accounts that have explicitly referred to four gas openings and 4 accounts that have possibly referred to four gas openings.

2 accounts have described one opening, but the descriptions do not - implicitly or explicitly - exclude that there were, in fact, more openings in the basement (thus I put them as "at least 1" in the summary table). 2 accounts stated there was more than one gas opening and four accounts did not specify the number of openings. 

The 2 remaining accounts have given a figure of three as the number of gas openings.

Thus, if we summarize the figures, two gas openings are can be supported with 3 accounts, three gas openings with 4 accounts and four gas openings with 16 accounts. Therefore, it is reasonable to conclude there had been four gas openings in the gas chamber's ceiling.

Gas introduction devices

18 of 26 accounts have mentioned or described a column leading down into the gas chamber. Those who commented on the material of the column have identified it as perforated metal/wire mesh. 

Auschwitz commandant Rudolf Höß described it was “fenced around with a grating”, SS investigator Konrad Morgen remembered it as “grilled shaft”, and the SS officer Josef Erber explained it consisted of “four iron bars...encased by steel wire mesh".

The Polish prisoner Michal Kula described them as "columns of wire netting" made of "3 mm iron wire stretched over angle irons", the Soviet prisoner Ananij Petko and Vladimir Pegov as "lattice-work columns", the Jewish prisoner Henryk Tauber as “made of grills of thick steel wire”, the Jewish prisoner Paul Bendel as "mesh tubes", the Jewish prisoner Miklos Nyszli as "sheet-iron pipes, the sides of which contained many perforations", the Jewish prisoner Filip Müller as "hollow columns...surrounded by perforated sheet", the Jewish prisoner Josef Sackar as "pillars with cages around them", the Jewish prisoner Shaul Chasan as "latticework shaft...made of perforated metal", the Jewish prisoner Yehuda Bacon as "steel bars surrounded by thick fence wire", the prisoner Michel Scheckter as "latticework chimney-like structures" and the Jewish prisoner David Olere draw them as four bars surrounded by wire mesh.

These descriptions are well corresponding and are primarily referring to the same outer structure of the device. The variants wire mesh and perforated metal, though technically different, are similar and could have been easily confused. 

In the German edition of Gideon Greif's "Wir weinten tränenlos...", Chasan is quoted as having described the metal column as "round", which is lacking in the English edition, however. The device was actually square according to most testimonies, either the German translation was inaccurate or Chasan is mistaken on the shape of the column.

The inner part of the column is known from fewer sources. The most detailed description is from Michal Kula, who took part in the construction of the device and mentioned a second wire mesh fixed inside. This was also testified by Henryk Tauber at his interrogation of 27-28 February 1945 (Mattogno, Auschwitz Lies). At a later deposition, Tauber mentioned a third fixed wire mesh, but which is most likely mistaken in the light of Kula's account and Tauber's own earlier description.

Kula also described that there was a movable inner column made of wire mesh with a central cone to distribute the pellets to the sides. Because of the large number of details provided by him on the device and his position in the metal workshop, Kula has to be taken as a primary witness on the columns - unless a detail is clearly contradicted by substantial evidence. Thus, the mobile inner part described by Kula was likely constructed and used at least in the beginning. Filip Müller mentioned there was a “spiral” inside the column to “distribute the gas”. This is possibly a misleading and misunderstood reference to the cone described by Kula. 

For Henryk Tauber, the movable inner part was a “box”, which could be regarded as a very simplified and somewhat inaccurate description of Kula’s mobile column. On the other hand, Josef Erber’s “sheet with low edge” is hardly compatible with Kula’s account anymore and suggests that the more complex and bulky device may have been later replaced by Erber’s simpler container. Both Tauber and Erber agreed that the mobile part was lifted up with a wire.


Several witnesses, Henryk Tauber, Henryk Porebski, Yehuda Bacon, Dov Paisikovic, Stanislaw Jankowski and Miklos Nyiszli, have mentioned chimnies on top of the openings. The roof was supposed to be covered with soil and grass (according to Henryk Tauber and construction documents), which might explain the difficulty for many witnesses to notice and characterize the chimnies. The chimneys are in fact most likely visible on a February 1943 ground photograph still showing the bare roof and not yet covered by soil (see also section on ground photographs). 

Chimneys are certainly a reasonable feature to provide protection against water and to allow burying the basement under the earth.  It is usually assumed that the chimnies were made of brick, which seems the most reasonable choice, but so far, I could not find direct confirmation for this in the eyewitness accounts. So it cannot be ruled out that the chimney were of different material like concrete.

The covers of the gas shafts were described as “concrete” by five witnesses, while Josef Erber remembered an “iron cover”. The “glass” version provided by Jaacov Gabai is very doubtful, not corroborated and can be rejected as severe memory fading or hearsay knowledge. Early evidence from the transfer inventory of crematorium 2 suggests that a wooden cover was used in the beginning.


The civilian engineer Karl Schultze stated that there were four openings of 25 x 25 cm in the roof, Yehuda Bacon estimated the column to be 40 x 40 cm and Michal Kula recalled the dimension of the column as 70 cm x 70 cm. Strictly speaking, we have to consider two sets of openings and columns, those of crematorium 2 and those of crematorium 3, which did not necessarily have the same dimensions. Crematorium 2 was completed and used much earlier so that modifications might have been incorporated in crematorium 3. 

Without taking into account other evidence, it would appear reasonable to assume the opening and device to be at the order of 70 x 70 cm as estimated by Kula, since he is the first choice witness on the device. However, according to physical evidence (see the respective section), which trumps testimonial evidence (when misinterpretation of physical evidence can be excluded at least), the openings in the roof of the gas chamber of crematorium 2 were somewhat less than 50 x 50 cm.

There are in principle three explanations for the apparent contradiction of the physical evidence with Kula’s account: a) Kula was referring to the device of crematorium 3, which was larger than the device of crematorium 2 in this case, b) he was mistaken with respect to the dimension, c) his description is incomplete/inaccurate and did not mention that the outer wire mesh was not penetrating the roof. Which of the explanations is actually true is hard to say for now without additional evidence. 

Counter witness

As far as I know, there is a single account doubting the existence of gas openings. The German civilian engineer Walter Schreiber and former chief inspector of Huta in Kattowitz stated that he did not remember about openings in the reinforced concrete roof of the cellars and that he would have objected against the construction of openings in the roof. But there is a severe problem with the testimony. 

Schreiber stated that he did not know anything about gas chambers in the crematoria 2 and 3, but it is well known from documentary evidence that gas chambers were actually installed in the basement (Pressac, Technique, p. 432). Furthermore, he makes no mention of the fact that workers of his own firm helped to install gas chambers at least in crematorium 5, where they fitted the gas-tight doors (Pressac, Technique, p. 407). It is therefore clear that Schreiber's knowledge on what was going on at the crematoria construction sites was either minimal and insufficient or he was suffering severe memory fading at the time of the testimony (not surprisingly at the age of 90). In any case, his single, isolated, late and uncorroborated account is not suitable to shed serious doubts on the existence of the openings. 

Ground photographical evidence

A ground photograph taken by the SS in February 1943 is showing three cuboids on the roof of the homicidal gas chamber of crematorium 2. The location of the cuboids corresponds well with the location of the gas openings identified by archaeological evidence (see the section on physical evidence below), as shown by the overlap of the model of the building based on the blueprints and the physical findings with the ground photograph as published by Harry Mazal, Daniel Keren, Jamie McCarthy here

I tried to verify the result by modelling the basement myself and feeding it with the physical findings. The match of my model with the ground photograph also shows good agreement and confirms the result.

A fourth object is visible between the left and middle cuboid, and it was speculated whether this is the fourth gas chimney (which existence is, in general, suggested by testimonial, aerial photographic and documentary evidence). However, if it interpreted as a gas chimney, it was located on the southern half of the basement, as already the two south-most chimneys, resulting in a quite inhomogeneous distribution of the gas inlets, which seems unreasonable from a technical point of view and is further contradicted by some testimonial evidence. Moreover, it looks distinctly different from the other objects assigned as gas chimneys. For these reasons, it is likely not the forth gas chimney. Its exact origin remains uncertain, but it is possibly some kind of construction material.

The most likely location of the forth gas chimney is indicated in the models above, assuming homogenous (my model) or fairly homogenous (Mazal et. al.) distribution and a left-right alternation as indicated by the position of the other three gas chimneys. According to this, the forth chimney is probably covered behind the smokestack of the little train in the foreground.

Another photograph taken earlier in January 1943 shows the gassing basement of the crematorium without the chimneys, which demonstrates they were constructed between both pictures. But it is not possible to tell from the photograph whether the gas openings are in the roof or not, since a) the basement is covered by snow and b) there is almost no view on the actual roof surface from the perspective. However, the archaeological evidence indicates the openings were made when the concrete was poured and therefore that they were already in place at the time this photo was taken.

Aerial photographic evidence

In summer 1944, Auschwitz-Birkenau was overflown and photographed by the British RAF, the US Air force and German Luftwaffe. The RAF photographs published on the internet are of too poor resolution to allow rational analysis on the issue of activity on the gassing basements of the crematoria. Four available US Air Force and Luftwaffe photographs are compiled here.

The undressing basements (parallel to the main buildings) do not show any features on top of the basement. Except for the footage of 13 September 1944, the photographs do show four spots and interconnection of them of the gassing basement of crematorium 2. 

The September 13 1944 photograph shows the four spots very weak and faint but lacks the interconnection. This is possibly related to masking of the basement by smoke from the bombing of Birkenau. The photograph shows heavy smoke at the sewage plant south of crematorium 2 and smoke coverage of the security screen at the gassing basement as well as smoke plums between crematorium 2 and 3. 

The smudges are also visible on the 21 December 1944 photograph, but the two southernmost spots are only very weak and poorly pronounced, which could be related to dismantling activities (the undressing room seems to be already partially destroyed).

Four alternating spots, as well as some weaker spots near the southeastern and north-western corners, are visible on the aerial photographs of the gassing basement of crematorium 3. 

The absence of any features on top of Leichenkeller 2 (undressing room) and the presence of spots on top of the Leichenkeller 1 (gas chamber) are clearly corresponding with the use of the latter as gas chamber operated from above. The match of the number of spots on top of the gas chamber of crematorium 2 and the number of spots, which are most pronounced, on top of the gas chamber of crematorium 3 with the number of gas introduction openings derived from testimonial evidence is striking. In all cases, the number is four. 

However, it is clear from the size and the shape that the smudges cannot be the actual gas chimneys and their shadows (as correctly pointed out by some Revisionists). The actual origin of the smudges is not known for sure. It was speculated that the dark spots are compacted earth from movement at the gas chimnies, but Revisionist Carlo Mattogno correctly noted that the sand at least in the front yard of the crematorium did not lead to such features.

It was also proposed that there might be different growth pattern of grass on the roof due to acid environment upon washing the mobile gas devices or that there was vegetation only around the gas chimneys, to begin with. Mattogno suggested that the discolouration comes from bitumen emerging from the damage of the thin concrete layer on the roof. In any case, the numerical and distributional correlation strongly suggests that the spots are related to activity at the gas chimnies.

Overlaying the August 25 1944 US Air force photograph of crematorium 2 and crematorium 3 with the location of the gas openings according to physical evidence from crematorium 2, which corresponds well to the positions of the chimnies on the February 1943 ground photograph, indicates that the smudges include or are attached to the openings, which corroborates that they are related and due to activity at the gas chimnies.

According to aerial photograph expert Caroll Lucas, who analyzed the August 25 1944 photo with stereo imaging microscope, the roof of the gassing basement of crematorium 2 "contains four raised vents", but unfortunately he did not mark their location on an actual photograph. If these vents are the gas chimneys,
they should match (within the relevant error margin) the openings identified in the roof of the ruins today, but this cannot be verified for now without further contribution from aerial photograph experts.

Documentary evidence

The transfer inventory of crematorium 2 of 31 March 1943 lists four “wire mesh slide in devices” (Drahtnetzeinschiebevorrichtung) and “wooden covers” (Holzblenden) for the Leichenkeller 2 (undressing room). There are three correlations of the devices with the gas columns:

a) material correlation: both the gas columns and the devices mentioned in the document were made of wire mesh

b) numerical correlation: both the gas columns and devices mentioned in the document were four

c ) locational correlation: both the gas columns and the devices mentioned in the document were located in the basement of crematorium 2

On the other hand, there are two problems:

d) locational contradiction: the gas columns were located in the gas chamber, whereas the devices are listed for the undressing room

e) functional contradiction: The mobile part in gas columns was moved down by gravity, whereas the devices mentioned in the document seems to have been being pushed by some extra force.

The first problem can be quickly resolved. The gas chamber and undressing room are placed in columns after each other and designated as corpse cellar 1 and 2. This already allows speculating that the entry in question may have been switched between the two basements. The probability that such a mistake actually occurred is enhanced by the fact that the previous entry in the document, the number taps, was switched between the gas chamber and the undressing room. The clerk, who filled out the document, apparently thought that the line for the gas chamber was actually the undressing room and vice versa when he entered the number taps, hence there is a considerable likelihood that, as he went on to fill in the wire mesh slide in devices and the wooden covers, he did not notice his mistake and continued to switch the entries between the basements.

A solution for the second problem was offered by Roberto Muehlenkamp, who argued that the wire mesh slide device may not describe its function but the layout and construction principle. This interpretation sounds linguistically unusual and strange to me, but given the peculiarities and false use of some speakers not impossible and totally improbable.

Due to the absence of evidence that the devices were actually something entirely else and existence of numerous testimonial evidence on the gas devices in the gas chamber basement, the most likely interpretation of the document is that wire mesh slide in devices were the gas introduction columns, but were switched between the lines and mistakenly attributed to the undressing room.

The wooden covers were obviously only a temporary solution and later replaced by more robust concrete covers according to testimonial evidence.

Physical evidence

A research team consisting of Harry Mazal, Daniel Keren and Jamie McCarthy investigated the ruin of the gas chamber of crematorium 2 in the late 90s and spotted three suitable candidates for gas openings in collapses roof of crematorium 2 (see their paper The Ruins of the Gas Chambers: A Forensic Investigation of Crematoriums at Auschwitz I and Auschwitz-Birkenau). The location of the three openings in the ruin, as well as the projected location of the forth still missing opening, is shown here.

Before going into detail, it is reasonable to ask what actually characterizes a suitable candidate for a gas opening. The main element to look for is that there must be a concrete and reinforced steel free area in the roof (unless there is evidence the opening was filled in - and there is not). Also, it can be expected that the openings were not arbitrary placed but in a particular pattern/distribution and are of similar size. 

It is, however, not a requirement (but possible) to have four straight and intact edges (as in the assumed original state) because possible destruction needs to be taken into account. This destruction would not have been limited to the collapse of the roof after the support pillars were brought down with explosives, but may in fact also include direct dismantling work at the openings.

The candidate for opening number 1 (counting from south to north) is shown here. Photographic footage from 1945 shows that the opening already existed at the time. The opening has been enlarged since then, but this is only apparent for what is not considered part of the original gas opening anyway. There are drops of tar visible at a straight side of the opening, which suggests that the opening was already in place at the time the tar was put on the roof for waterproofing in early 1943

The candidate for opening number 2 is shown here, here and here. The cut and bend rebar indicates it was artificially made. 

According to Mazal et al., opening number 3 - if it exists, and the testimonial, aerial photographic and documentary evidence strongly suggests that it exists - is supposed to be in a badly damaged area not accessible without the removal of rubble.

The candidate for opening number 4 has been identified here. It shows cut and bent rebar and Mazal et al. noticed out that “both ends of this loop are firmly embedded in a large chunk of concrete to the east of the hole, contradicting any claim of tampering after the war”. 

The size of the three openings as indicated by the cut and bent rebar around them is about 50 x 50 cm. Since the concrete likely extended into the opening, the original size was somewhat less. They are located 75 cm from the centre of the roof. The distance between the openings 2 and 4 is peculiar significant compared to the distance of opening 1 and 2, which suggests that there is another opening (number 3) in between not identified so far, as also supported by testimonial, aerial photographic and documentary evidence.  

The arguments and photographs presented by Mazal et al. have been reviewed by a structural engineer, who concluded that “it is my professional view that the authors present a strong and sustainable case that openings described as zyklon vents 1, 2 and 4 were installed in the roof of the building during the course of construction”.


The key points of the body of evidence have been illustrated in this overview slide.
4 June 2014 [corrections re: Schreiber, Drahtnetzeinschiebevorrichtung]

22 November 2014 [added A. Dragon and S. Venezia]

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