The Walls of Auschwitz

A Chemical Study
Published: 2008-10-10

Three main chemical investigations have been performed concerning residual cyanide in the walls of alleged ‘gas chambers’ at Auschwitz: by Leuchter, Rudolf and by Markiewicz. Over the two decades since Leuchter first sampled, debates have raged concerning where the samples were taken from, whether it was really ‘historic’ brickwork, how porous the brickwork was to the cyanide gas, and so forth. And yet, it is here argued that some fairly definite conclusions can be drawn from them. In particular, the Leuchter and Rudolf results are seen to corroborate each other. There is a difficulty with the level of accuracy claimed by Markiewicz.

I. The Leuchter Report, 1988

In February 1988, Fred Leuchter came to the Auschwitz crematoria ruins, with his wife and a team,[1] With his fur hat and small hammer, he chiselled out 32 samples from floor, walls and ceiling of the ‘gas chambers,’ and Howard Miller bagged and tagged them. His Report published in April of 1998[2] contained five maps as appendices which indicated where the samples had been taken from, and in addition a film was made of his sampling.[3] The locations are important, because some of the ‘gas chamber’ locations are postwar-reconstructed, and the obtaining of original brickwork was essential for his purpose.

Leuchter in effect tested the hypothesis, as to whether or not certain large rooms, designated in the Auschwitz design-plans as either morgues or washrooms, had in fact been used for large-scale human cyanide gassing on a daily and lethal basis. As America’s foremost supplier of execution hardware, Leuchter was primarily concerned with whether it would have been feasible to perform such executions using the designated rooms; this however will not concern us here, our concern being solely with the wall samples he took.[4] These were analysed in March 1988 by Alpha Analytical Laboratories Ltd,[5] in ignorance of their source.

He managed to take one one sample of a ‘Disinfestation Chamber,’ by breaking and entering a locked building: but prowling guards and snowy blizzards prevented further sampling from a second such chamber at camp Majdanek.[6] His swiftly-published ‘Report’ in effect grouped his chemical data into two, that of the sample 32 which he called perhaps unfortunately his ‘control,’ and all the others, as the graph shows. The latter came from five ‘Crematoria’ sites in the Auschwitz complex.

Duality of the ‘Gas Chamber’ concept in Leuchter’s Report

The terms that will here be used, that are as far as possible non-judgemental, are AHGCs or alleged human gas chambers for what Leuchter called ‘Crematoria’ and DCs or disinfestation chambers for what in the German design-plans were called ‘gas chambers’ (gaskammers). The latter had been used in Germany since 1924, much as we would nowadays use DDT, for killing the flea that carried the typhus bacillus. They were operated using ‘Zyklon-B’ granules, composed of liquid hydrogen cyanide (boiling-point 27° C) that would evaporate over a couple of hours from its clay substrate. In the German labour-camps, clothing and bedding were repeatedly fumigated in such chambers. Prior to Leuchter’s work, pro – Holocaust books had not acknowledged such chambers, and had rather carried the message of the Nuremberg trials, whereby any use of Zyklon-B was merely presumed to have been for human extermination. After Leuchter, Pressac’s magnum opus reproducing design-plans of Auschwitz-Birkenau located and described the ‘Gaskammer’ or DCs.[7] These were quite a lot smaller than the AHGCs, and designed by the industrial-chemistry firm ‘Degesh.’ Pressac also observed that their walls tended to be blue: they had gradually developed that hue after the War, owing to their saturation with iron-cyanide.

Fred Leuchter found one thousand-fold difference in residual cyanide levels between these two types of ‘gas chamber’ – that designated in German design-plans as gas chambers, but whose existence was ignored at Nuremberg, and the much larger rooms alleged to have functioned as gas chambers. Together with Pressac’s acknowledgement of the DCs, this meant that future pro-Holocaust books would have to work with a duality: that the very same cans of ‘Zyklon-B’ were used for two extremely different purposes on the same campsite: for taking lives via the extermination procedure, whereby millions died, in the extraordinary manner described at Nuremberg, and also for saving them by combating the typhus epidemic. This did not make a great deal of sense and some noted that one could more readily have not bothered and just let the typhus epidemic do its work.

Leuchter's analysis of brick samples
Leuchter's Analysis of Brick and Mortar Samples taken at Auschwitz & Birkenau showing Total Cyanide (From The Leuchter Report) Click for full-size chart

There was controversy over the extent to which all of Leuchter’s samples had indeed been taken from walls of chambers allegedly exposed to the cyanide, given that much of the ‘gas chambers’ are now acknowledged to be postwar-reconstructed; as likewise there was disagreement over the extent to which exposed walls may have had any cyanide leeched out from them over six decades, a theme we return later on with the work of Mr. Dan Desjardins. The iron-cyanide bonding which takes place once the HCN has entered the brick and mortar of the walls, is permanent: the complex ferric ferrocyanide (Fe4[Fe(CN)6]3), otherwise known as "Iron Berlinate" or "Prussian Blue" is, according to The Merck Index, "... practically insoluble in water."[8] It is used as a pigment in printing inks and artists' colors, and remains stable in water, air, ultraviolet radiation and with the elevated temperatures of summer.

Following Leuchter’s discovery, some suggested that the DCs had been more heavily used than the AHGCs, after all did not beetles or fleas take longer to kill than humans? And, were not the DCs heated in order to promote the release of the HCN, and would that not give a higher degree of wall-absorption? Others replied that, if half a million people had allegedly been gassed in ‘Krema II’[9] over a two-year or so period then that would have been a rather intensive use, and not easily reconcilable with Alpha Analytical Laboratory’s finding that all seven wall-samples taken therefrom had levels of total cyanide too low to be measurable. Should not all the moisture from the body sweat, plus body heat, have rather promoted HCN absorption?

Others had a different criticism, that the cyanide gas would have only been adsorbed onto the wall surface, and that the concentrations found would to a large extent merely reflect the extent to which surface material of the wall had been scraped off, while deeper samples would hardly contain any. We leave these questions for now and review the two further chemical investigations, performed in the wake of Leuchter.

II. The Rudolf Report, 1993

…fortunately it is precisely the one ‘gas chamber’ in which the largest number of people was allegedly killed by poison gas during the Third Reich which has remained almost entirely intact: morgue 1 of crematorium II.’—Germar Rudolf[10]

Germar Rudolf found that the Leuchter Report ‘embedded the thorn of doubt in my heart’ while he was a PhD chemist at the prestigious Max Planck Institute. In 1991 he visited Auschwitz and took 24 samples, analyzed by the Fresenius Institute using a comparable procedure.[11] He was later criticized for having used the Max Planck Institute notepaper for having asked them to do this, without explaining where they had been taken from. Both Leuchter and Rudolf used their professional position to request the chemical analysis, and both had their professional existence terminated by that act.

Although Rudolf’s sample-taking was photographed, he was criticized for not having had enough by way of witnesses checking his sample-taking and how the containers were labeled for his thirty-odd samples. Both Leuchter and Rudolf took their samples without having obtained permission – which assuredly would not have been given, had they asked. The samples were boiled for an hour with hydrochloric acid to drive out the cyanide gas, collected by absorption with caustic potash, then assayed photometrically. The method gave cyanide levels down to 0.1 – 0.2 ppm in the mortar, obtaining measurable values for almost all of his samples, despite which Rudolf remained doubtful over the value and reproducibility of results below several parts per million.[12]

He sampled extensively both from the inside and outside of the blue-stained DCs at Birkenau, where his grouped results were:

Table 1: Mean Cyanide DC Birkenau wall-sample values, Germar Rudolf data, 1991[13]
Delousing room, inside:5830 ± 3700 ppm(n=10)
Delousing room, outside:3010 ± 3600 ppm(n=5)

This indicates that the cyanide gas was able to penetrate right through the brick walls, and would not merely have been absorbed onto the surface; and suggests that weathering over half a century has not greatly affected the cyanide concentrations. This data has a central importance, because Leuchter had only managed to take one single sample of delousing chamber wall.[14]

The ‘Control’ samples of Germar Rudolf

Rudolf only took three samples from the AHGC walls (from what is called the Krema-II morgue), which was the weakness of his survey. Their wide divergences (7.2, 0.6 and 6.7 ppm) give little idea of this key parameter.[15] He took more samples from ‘controls’ – i.e., rooms where no-one had alleged that systematic cyanide gassing had taken place. His ‘control’ group is here subdivided into samples taken from the mortar between the bricks, and the rest\.

Table 2: As before, sampling AHGC walls vs ‘controls’
AHGC walls:4.8 ± 3 ppm(n=3)His samples 1-3 of Table 19
Controls, plaster:1.1± 1.3 ppm(n=6)His samples 4,5,7,8, 10, 23
Controls, mortar:0.2± 0.1 ppm(n=3)His samples 6,21,24

This indicates a significant elevation of residual cyanide in the AHGCs.

The Ball Report 1993

It is hard to obtain copies of this Report, or to gain details of where the chemical analysis was performed.[16] J.C. Ball has a degree in geology, and worked as a mineral exploration geologist. Given the intensity of criticism to which anyone publishing in this area is exposed, one should perhaps refrain from criticism on this matter. Its six samples were:

Table 3: Mean values of the cyanide measurements found by John Ball, 1993
From a DC:3000 ppm(n=2)
From AHGC sites:0.5 ± 0.6 ppm(n=4)

III. The Markiewicz et. al. Polish Study of 1994

The director of the Auschwitz museum Franciszek Piper approached Dr Jan Markiewicz of the Jan Sehn Institute of Forensic Research at Cracow as to whether they would check over the residual cyanide levels, in the wake of the Leuchter Report. On 20 Feb 1990 Dr. Wojciech Gubala arrived and removed 22 samples, including two control samples. The team then decided that they would like to follow this up with a further study before publishing any results.

This survey, published in 1994, differed from those of Leuchter and Rudolf in that it only looked at soluble cyanide in the brickwork.[17] Critics objected that it was precisely the soluble component of cyanide which one would not expect to provide a memory of the past, because it would clearly be affected by weathering. Their reason for using such a method was, apparently, that they did not want to get involved in debates over Prussian Blue formation: their approach ‘excludes the possibility of the decomposition of the relatively permanent Prussian blue, whose origin is unclear in many parts of the structures under investigation,’ and therefore ‘The real level of total cyanide compounds could therefore be higher than shown by our analysis.’ The samples were put in 10% sulphuric acid for 24 hours, thereby driving off the cyanide as before, except that cyanide bonded to iron was not liberated by the Polish method – the point of which has not been clear to a lot of people.

The soluble or non-bonded cyanide thereby measured was only present in low concentrations measured in parts per billion rather than parts per million. How were they able to attain this accuracy in measurement unattainable either by Alpha Analytical laboratories or the Fesenius Institute? The method they referenced for this analysis had been published in 1947, and could one expect this to attain these much higher levels of accuracy? From three ‘gas chambers’ they found:

Table IV: Polish data. Mean levels of soluble cyanide in Crematoria walls, 1994
AHGC walls, Krema I:0.07 ± 0.1 ppm(n=7)
Krema II:0.16 ± 0.2 ppm(n=7)
Krema III:0.03 ± 0.02 ppm(n=7)

These samples averaged 90 parts per billion. The Polish group claimed that their method could measure down to 2-3 parts per billion. For their ‘control’ they took eight samples from three different residential blocks, and thereby obtained (or at least published) consistently zero values – i.e., zero parts per billion! How impressive to have discovered this ultra-sensitive method. As ‘holocaust’ chemist Dr Richard Green explained, ‘ The IFFR used a much more sensitive method. Their sensitivity was 3-4µg/kg, i.e., 300 times more sensitive.’[18] If that method published in 1947 had such astounding accuracy, then why did subsequent chemists fail to use it?

This investigation gave DC wall-concentrations in its Table 4, finding a several-fold elevation in cyanide levels there. Eight values for ‘concentrations of cyanide ions in samples collected in the facilities for the fumigation of prisoners clothes, (Birkenau Bath-House Camp B1-A)’ gave a mean value of 273 ppb, thrice that of the ‘Kremas.’ Their conclusion omitted comment upon this highly significant elevation. This paper has been much cited by pro-Holocaust sources, as refuting the Leuchter Report, by demonstrating that the AHGCs (‘Kremas’) had raised cyanide as compared to ‘controls.’ The paper was entitled, ‘ A study of the cyanide compound contents in the walls of the gas chambers in the former Auschwitz and Birkenau concentration camps’ It thus used a Nuremberg-type terminology, where ‘gas chamber’ simply meant a place for human extermination. They could hardly have done otherwise, because doubt over ‘the Holocaust’ is a crime in Poland. The DCs were alluded to as ‘Facilities For the Fumigation of Prisoners' Clothes.’

The Polish team went to a lot of trouble, with some sixty measurements mostly measured thrice, and was the only study which obtained permission to take the samples. It omitted two things in its conclusions: any allusion to the Birkenau DC (‘facilities for the fumigation of prisoners clothes’) where it had found greatly-elevated cyanide levels over the AHGCs; and, the insoluble cyanide that was bound to iron. In regard to both of these it cited the Prussian blue ferric ferrocyanide complex, leaving open the possibility that is had some quite extraneous source and was therefore to be avoided. 

The 1947 method used by Markiewicz et. al. was given by Joseph Epstein and published in a US chemistry journal.[19] It was a procedure whose limit of accuracy was given as 0.2 micrograms per ml. To expel the cyanide from brickwork and then dissolve it into a solution suitable for measuring it, involves an order-of-magnitude dilution at least, so that one would not expect to obtain an accuracy less then one ppm in the brickwork, using this method. Any claim that this decades-old titration and colorimetric method using thiocyanate can find parts per billion has to be spurious.

IV. Desjardin analyses Leuchter

Dan Desjardins, after carefully retracing the steps of Leuchter on a 1996 visit to Auschwitz,[20] and watching the film that had been made of Leuchter’s sampling,[21] divided the samples 1-31 into two groups: those which had been exposed and open to the elements over the decades (n=20) , and those which were more protected in sheltered, unexposed locations : ‘Leuchter's samples, numbered 25 through 31, extracted from Crematorium I… taken from a facility which was not destroyed and has remained intact since the end of the war, were not exposed to the elements. The same might be said for samples 4, 5 and 6 taken from Crematorium II. Leuchter removed these samples from a pillar, wall and ceiling which, though accessible, were nevertheless well protected against wind, rain and sun.’[22]

Less then half (14 out of 35) of Leuchter’s samples had measurable levels of cyanide in them, where measurable means above one part per million. We have here assigned an arbitrary value of 0.5 ppm for those too low to measure, i.e below 1 ppm. This gave:

Table 5: Desjardins grouping of the Leuchter data as ‘sheltered’ or ‘exposed’ (2007)
Sheltered(n=10)1.88 ± 2.2 ppm
Exposed(n=20)1.31 ± 1.56 ppm

The ‘exposed’ group scored 30% lower than the sheltered group, a result which lacks statistical significance (t=0.8). This data could suggest that one-third of the cyanide had leeched out from the exposed walls, over sixty years; if indeed they had all at one historic period been exposed to hydrogen cyanide.

Mr Desjardins further subdivided the Leuchter samples into those taken from AHGC walls, and those which were ‘controls’ i.e. taken from barracks, etc. The definition of the ‘control’ concept is critical here, and means brickwork where no one has been concerned to allege that is was part of a room where systematic cyanide gassing took place – whether of humans or of mattresses. Leuchter surmised that the ‘control’ sample had been exposed at some stage to a single fumigation by cyanide gas, by way of cleaning out any lice from cracks etc.

Table 6: Desjardins groups Leuchter’s data by AHGC versus ‘controls’
AHGCs(n=19)1.63 ± 2.1 ppm
Controls(n=9)1.45 ± 1.2 ppm

This result too lacks statistical significance, i.e. Leuchter’s sample provides no evidence for human ‘gas chambers’ having raised residual cyanide levels above those of ‘controls.’ The data suggests that the AHGCs did not ever function as lethal gas chambers.

These two sets of data (using Desjardins’ divisions) co-vary somewhat, in that if we increase the ‘exposed’ samples by say 25%, to allow for leeching out of their cyanide over the decades, then the difference between the AHGC and ‘control’ groups disappears altogether. (As Mr Desjardins put it, five times as many of these [AHGC] samples came from locations protected from 40-years’ exposure to wind and rain.’) Mr Desjardins concluded, ‘Fred Leuchter’s broad sample gathering, despite flaws, establishes a reasonable basis for inferring that the presence of cyanide residue is due to benign rather than homicidal purposes.

What Desjardins meant by ‘flaws’ in Leuchter’s methodology was, he explained, that a not sufficiently constant ratio had been maintained between amount of surface wall or plaster included per sample, and overall volume. This he viewed as producing a variability in the data, but not as discrediting the investigation per se, as one finds claimed in certain quarters.[23]


  1. One might expect that the accuracy of cyanide-ion assay would have increased substantially over the last couple of decades, but this is not the case: any re-analysis of the brickwork would face the same frustrating situation, where differences between AHGCs and controls hover right next to the lowest detectable levels.
  2. The essential questions here reviewed may be best evaluated without arguments over whether or not Prussian blue colouration has formed. The latter involves a slow and complex sequence of reactions. We have here been primarily concerned with total cyanide in the brickwork.
  3. Plaster on the wall-surface may tend to have a higher cyanide level than brick or mortar underneath it, and the ferric-ferrocyanide does decrease as a function of depth. Samples should therefore aim to have a comparable breadth-to-depth ratio.
  4. The notion of a ‘control’ sample has developed from Rudolf’s sampling and also from Mr Desjardins evaluation of the Leuchter sample locations. This permitted an evaluation of whether measurement of authentic AHGC wall were significantly elevated over such. While there was a hint of this from Rudolf’s sampling, and while further investigation might confirm this, overall no statistically significant elevation was evident.
  5. The careful and extensive Polish data was analysed using a 1947 US titration procedure, which gave no indication of reaching the parts per billion accuracy claimed by that study. If Marciewicz et. al. chose to use a method which only analysed 1% or less of the cyanide, viz. the soluble component, for whatever reason, they should first have shown that their method was capable of detecting it. 
  6. Both the Leuchter and Rudolf surveys obtained a three order-of-magnitude differential between the walls of DC and AHGC buildings; the simplest explanation of which is that the former was used on a regular basis for cyanide fumigation while the latter was not.
  7. The Leuchter data showed that there was no great diminution of cyanide levels due to weathering over half a century, and this accords with what is known about the insolubility and permanence of the ferric-ferrocyanide complex. The residual cyanide within those walls may therefore offer the most reliable memory which the human race now has, concerning what happened historically in German ‘gas chambers.’


Leuchter 1988 Table of Data, Alpha Laboratory measurements plus Desjardin critique (2007)
Test Sample Location (Leuchter) Total cyanide, ppm Sheltered/Exposed (Desjardins) AHGC/Control (Desjardins)
1 Crema II, Morg. 1 - Exposed AHGC
2 Crema II, Morg. 1 - Exposed AHGC
3 Crema II, Morg. 1 - Exposed AHGC
4 Crema II, Morg. 1 - Sheltered AHGC
5a Crema II, Morg. 1 - Sheltered AHGC
5b Crema II, Morg. 1 - Sheltered AHGC
6 Crema II, Morg. 1 - Sheltered AHGC
7 Crema II, Morg. 1 - Exposed AHGC
8a Crema III, Morg. 1 - Exposed AHGC
8b Crema III, Morg. 1 1.9 Exposed AHGC
9 Crema III, Morg. 1 6.7 Exposed AHGC
10 Crema III, Morg. 1 - Exposed AHGC
11 Crema III, Morg. 1 - Exposed AHGC
13 Crema IV - Exposed
14 Crema IV - Exposed
15 Crema IV 2.3 Exposed Control
16 Crema IV 1.4 Exposed Control
17 Crema IV - Exposed Control
18 Crema IV - Exposed Control
19 Crema IV - Exposed Control
20a Crema IV - Exposed AHGC
20b Crema IV 1.4 Exposed AHGC
21 Crema V 4.4 Exposed Control
22 Crema V 1.7 Exposed Control
23 Crema V - Exposed Control
24 Crema V - Exposed AHGC
25a Crema I, Morgue 3.8 Sheltered AHGC
25b Crema I, Morgue 1.9 Sheltered AHGC
26 Crema I, Morgue 1.3 Sheltered AHGC
27 Crema I, Morgue 1.4 Sheltered AHGC
28 Crema I, Wash rm 1.3 Sheltered Control
29 Crema I, Morgue 7.9 Sheltered AHGC
30a Crema I, Morgue 1.1 Sheltered AHGC
30b Crema I, Morgue - Sheltered AHGC
31 Crema I, Morgue - Sheltered AHGC
32 Disinfestation Rm 1,050


For details of who went with Leuchter, and helped with the samples, see: Stephen Trombley, The Execution Protocol: Inside America's Capital Punishment Industry, NY, 1993.
Fred Leuchter, An Engineering Report On The Alleged Execution Gas Chambers At Auschwitz, Birkenau and Majdanek Poland, Samisdat Publishers, Ltd., 1988 (known as ‘The Leuchter Report’).
Film of Leuchter sampling "Leuchter in Poland," Samisdat Press, Ltd., Toronto.
Data-page from Alpha Laboratories:
Dr. James Roth, Manager and Chief Chemist of Alpha Analytic Laboratories, Ashland, Massachusetts, testified concerning his analysis at the April 1988 trial of Ernst Zundel in Toronto.
Jean-Claude Pressac, Auschwitz: Technique and Operation of the Gaschambers’ NY 1989.
An Encyclopedia of Chemicals, Drugs, and Biologicals, 12th edition, 1996, p. 683.
This is sometimes alluded to as “Birkenau Krema I”.
Germar Rudolf, The Rudolf Report, expert Report on Chemical and Technical Aspect of the Gas chambers of Auschwitz, 2003 (1st Edn 1993), p. 146; cf ‘It was decided to transform morgue I of crematorium II into a gas chamber:’ Y. Gutman & M.Berenbaum, Anatomy of the Auchwitz Death Camp 1994, pp 183-245 J.-C. Pressac & R.J. van Pelt, ‘The Machinery of Mass Murder at Auschwitz’, p. 223.  
G. Rudolf, Das Rudolf Gutachten, Cromwell, Press London 1993 (I haven’t seen this). The analytic method is given in DIN 38 405, section D13 (Deutsche Institute fur Normung).
The Rudolf Report , 8.3.3, Table 19; also Table 3 in ‘Dissecting the Holocaust’ Chapter by GR.
Dissecting the Holocaust 2003 Table 3 of Rudolf Ch.
For his difficulties here, see:
Table 19, p. 254 of The Rudolf Report 2001.
John Clive Ball, The Ball Report, Ball Resource Services Ltd., Canada 1993; The Rudolf Report, p.268.
Jan Markiewicz et. Al., Z Zagadnien Sqdowych z. XXX, 1994, 17-27.
Richard Green 'A study of the Cyanide Compound Content in the Walls of the Gas Chambers in the Former Auschwitz and Birkenau Concentration Camps,' in John C. Zimmerman, Holocaust Denial: Demographics, Testimonies and Ideologies, U.P.Amer., 2000, pp.259-262.
Joseph Epstein, ‘Estimation of Microquantities of Cyanide’, Industrial and engineering Chemistry 1947, 19, 272-274.
D. Desjardins: Kenneth Stern's Critique of The Leuchter Report: A Critical Analysis, March, 1997
"Leuchter in Poland," ref. 3.
Desjardins, The Leuchter Report revisited
The criticism made by chemist Dr James Roth, interviewed in the 1999 film about Leuchter ‘Mr Death,’ was along these lines: the cyanide would penetrate a mere ten microns into a wall, he there averred.

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Author(s): Nicholas Kollerstrom
Title: The Walls of Auschwitz, A Chemical Study
Published: 2008-10-10
First posted on CODOH: Oct. 8, 2008, 7 p.m.
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