The Truth about the Leuchter Report Part Two


This article was first published in Hard Evidence, Vol. 8, No. 6, November-December 2008)


The absence of Iron Blue

Leuchter’s design and engineering criticisms of the Auschwitz gas chambers were unfounded and have been discredited. However, the Leuchter Report also contained forensic arguments. Leuchter took samples from the reconstructed gas chamber in Auschwitz I, the ruins of the four gas chambers in Birkenau and a delousing chamber in Birkenau. The samples taken from the gas chambers revealed very low traces of cyanide. The highest was 7.9 mg/kg from a sample taken from Crematorium I. No cyanide residue was found in any of the samples Leuchter took from Crematorium II. In contrast, the “control sample”, which he took from the delousing chamber, contained 1,050 mg/kg of cyanide.” (1) Leuchter wrote,

“The absence of any consequential readings at any of the tested locations as compared with the control sample reading of 1,050 mg/kp supports the evidence that these facilities were not execution gas chambers. The small quantities would indicate that at some point these buildings were deloused with Zyklon B – as were all the buildings at these facilities. Additionally the areas of blue staining show a high iron content, indicating ferric-ferro-cyanide, no longer hydrogen cyanide.

One would have expected higher cyanide detection in the samples taken from the alleged gas chambers ( because of the greater amount of gas allegedly utilized there) than that found in the control sample. Since the contrary is true, one must conclude that these facilities were not execution gas chambers, when coupled with all the evidence gained on inspection.” (2)

In 1991 another revisionist Germar Rudolf also took samples from Auschwitz with similar results which he published in the Rudolf Report. (3)

On the surface, Leuchter’s forensic findings could appear convincing, however they do not stand up to scrutiny. Leuchter was not looking for hydrogen cyanide gas residue in the gas chamber bricks. He was looking for ferric-ferro-cyanide or Iron Blue which he assumed would form when the cyanide in the gas reacted with the iron in the bricks of the gas chambers. He believed the walls of the gas chambers consisted of ordinary, unprotected bricks (4), so he thought the hydrogen cyanide gas would have been in direct contact with the bricks, making it more likely that Iron Blue would form. He could not tell that the brick walls had been coated with cement. The remains of this cement coating can still be seen in Crematorium II (5). This coating would have protected the bricks from the gas, making it less likely, if not impossible, for the cyanide to react with the iron in the bricks and form Iron Blue (6).

An obvious reason why some of his samples did not contain any cyanide residue was that they did not come from any of the gas chambers. Leuchter did not know that after the war, the walls of the demolished Crematoria IV and V were rebuilt to about a metre high, using bricks from only Crematorium V (7). Bricks, which he thought were part of the gas chambers, could have come from somewhere else in Crematorium V. However, Leuchter did not even know where the gas chambers were in Crematoria IV and V. He took eight samples from Crematorium IV. None of them were from where the gas chambers were. Four were from the undressing room. Two of these contained cyanide, suggesting they originally came from the gas chambers in Crematorium V. Two other samples came from the doctor’s room and the last two were from the coal room. He took four samples from Crematorium V. Only one of these came from one of the gas chambers and it contained no cyanide residue, suggesting the material was originally from somewhere else in the building (8)

Likewise, Crematorium I is a reconstruction. Since being used as a gas chamber, it was converted into an air raid shelter, and after the war into a replica of a gas chamber. The walls were resurfaced. Interior walls were added, then removed. Leuchter did not consider that this would have affected the amount of cyanide found in the samples he took. Nevertheless, Leuchter did find more cyanide residue in Crematorium I than the other gas chambers (9). Jean Claude Pressac has suggested that by finding cyanide residue, Leuchter has inadvertently proved there was a gas chamber in Crematorium I;

“If Leuchter’s results are confirmed by official toxicological testing, Leuchter, in spite of his intentions, will have provided the irrefutable material proof of its homicidal use which historians were lacking.”(10)

The Focal Point edition of the Leuchter Report is subtitled, “The First Ever Forensic Examination of Auschwitz.” This is not true. The Poles carried out a forensic investigation after the war and found traces of cyanide in Crematorium II. The 1945 report German Crimes in Poland says,

“In the women’s hair which was cut after they had been gassed, and in the zinc lids of the air-exhaustion openings of the gas chamber (Leichenkeller 1) of Crematorium II, and finally in the metallic objects hairpins and clasps, and the metal spectacle-frames, found in the bag of hair, an expert chemical investigation carried out by the Legal Expert Inquiry Institute at Cracow found traces of hydrogen cyanide and a relatively large quantity of its compounds (report of Dec. 14, 1945).” (12)

Except for Crematorium II, Leuchter did find some cyanide residue in the gas chambers, but he did not accept that these small amounts of cyanide could have been evidence they were gas chambers. He said it was because they had been deloused with Zyklon B at some stage. (13) Elsewhere in the Leuchter Report, Leuchter argued that if the SS had used Zyklon B to kill people in these rooms, they would have poisoned themselves, caused an explosion and gassed “the entire camp.” (14) However, he also believes the SS were able to use Zyklon B to kill lice in the same rooms without apparently blowing up the building and killing themselves and everyone else. Again, revisionists seem to think that the chemical properties of Zyklon B change depending on whether it is used for killing lice or people.

If no cyanide residue were found, Leuchter argued this meant there were no gas chambers. If any cyanide were found, they still would not accept this as scientific evidence of homicidal gassings. They claimed that the morgues had been deloused with Zyklon B. It appears that no matter what the forensic results, Leuchter had an explanation and was going to say they proved there were no gas chambers.

Leuchter’s flawed “science

Whether or not the small traces found by Leuchter and others should be considered as proof of homicidal gassings depends on how much cyanide residue one would expect in a gas chamber after 40 years. A person conducting a real scientific forensic examination of Auschwitz would take a control sample from an American gas chamber, which had not been used for a few decades, and then compare the cyanide residue, if any, in the control sample with the amounts found in Auschwitz.

Leuchter used a sample from a Birkenau delousing chamber as a control sample, but a gas chamber and a delousing chamber are not the same and did not work the same way. As we shall see, the walls of the delousing chambers were exposed to the gas for a longer period of time. The lack of a proper control sample means Leuchter’s forensic findings are scientifically worthless and do not prove anything.

During the Zundel trial Leuchter was asked under cross-examination whether he would expect to find any cyanide residue in one of his gas chambers after forty five years. He said no (16), but that did not stop him from arguing that the low levels of cyanide found in Auschwitz are proof they were not gas chambers.

Leuchter’s answer was apparently influenced by his mistaken belief that there was no ventilation in the Auschwitz gas chambers. He believed it would have taken a week to ventilate the rooms naturally, so the gas would have had a long time to react with the iron in the bricks, whereas American gas chambers had mechanical ventilation leaving less time for a reaction to occur. As we have seen, Leuchter was wrong about the ventilation in Auschwitz, so his opinions about cyanide residue are built on a false foundation.

The forensic tests of Leuchter and Rudolf were intended to find cyanide residue in the form of Iron Blue or Prussian Blue which was supposed to have formed when the hydrogen cyanide gas reacted with the iron in the bricks of the gas chamber walls. The walls of the delousing chamber in Birkenau contain blue stains which are apparently the result of exposure to hydrogen cyanide gas. Leuchter appears to believe that Iron Blue will always form when bricks containing iron are exposed to hydrogen cyanide gas, so its absence supposedly proves the gas was not used and they could not have been gas chambers. (17)

In the book Auschwitz Lies Germar Rudolf cites the 1977 case of a Bavarian church which was deloused and blue stains appeared on the walls, giving the impression that this is what happens when buildings are deloused with Zyklon B;

“That the development of bluish patches on the surfaces of walls similar in appearance to those on the walls of the Auschwitz delousing chambers is the consequence of HCN gassing can be shown dramatically by one reference in the technical literature. In 1981, the periodically published journal Bauschaden Sammlung (Collection of Construction Damages) reported about the effects of a hydrogen cyanide gassing on a church that had been freshly plastered a few weeks before. In that case deep blue patches appeared all over after several months.” (18)

However in another book, Lectures on the Holocaust, Rudolf acknowledges that this incident was an exception (19). If Zyklon B produced Iron Blue and damaged the building by turning the walls blue every time it was used, it would have been commercially useless.

Clearly, it is possible that the walls could have been exposed to hydrogen cyanide but other factors meant the gas did not react with the iron in the bricks to form ferro-ferri-cyanide or Iron Blue, so it evaporated or was washed away, leaving little or no trace. Germar Rudolf says in the Rudolf Report that this happened in the delousing chamber in Dachau;

“To my knowledge, only the Zyklon B disinfestation chambers of Dachau camp (DEGESCH circulation chambers) exhibit no blue pigmentation, because the walls were professionally coated with a paint impermeable to gas and water.” (20)

Would Iron Blue have formed at all?

The real issue is would Iron Blue have formed on the walls of the Auschwitz gas chambers if they had been used as described by the historical evidence. Revisionists claim that it should have. However, real scientists do not simply say what they think or want to believe should happen. They carry out experiments to prove or disprove whether what they think should happen (their hypothesis), really would happen. A real scientist, who wanted to find this out, would replicate the conditions in the gas chambers. He would find a brick room, coat the walls with cement, make it gas-tight and add a mechanical ventilation system. Then, he would add the Zyklon B and some carbon dioxide to simulate the effect of the victims exhaling. He would pump out the gas after about 20 minutes, wash the walls and let it dry. He would repeat the process (ideally about 180 times). Then, he would wait a few years, remove part of the cement coating and take some samples from the bricks underneath and see how much Iron Blue had formed. Finally, he would compare his findings with samples taken from the Auschwitz gas chambers.

The only experiment, which Germar Rudolf describes carrying out in his report, involved trying to form Iron Blue in a cold (11 degrees Celsius), damp container by exposing building material to 20,000 ppm (parts per million) of hydrogen cyanide for 24 hours (21). He found traces of Iron Blue (22), but since the walls of the gas chambers were not exposed to 20,000 ppm of hydrogen cyanide for 24 hours at a time in cold, damp conditions, these results are irrelevant. If he could conduct this experiment, I wonder why he did not conduct one which more accurately reflected conditions in the gas chambers.

In Auschwitz Lies, Rudolf has admitted exposure to hydrogen cyanide does not always result in Iron Blue and he has not conducted any experiments to prove or disprove whether it would have formed in the gas chambers,

“Again I do agree with him [Richard Green] to a certain degree: An exact answer to the question: “Could long term stable Iron Blue compounds be formed by human gassings, and if so, which amount would be formed?” would indeed require large scale experiments, for which I do not have the necessary means. At any rate the widespread assumption that one or several gassings with Zyklon B automatically and under any circumstances lead to traceable cyanides residue is incorrect.” (23)

If Rudolf agrees that exposure to hydrogen cyanide gas does not always produce Iron Blue and he has not conducted any experiments to determine whether it would have formed in the Auschwitz gas chambers, then from a scientific perspective the forensic evidence of Leuchter and Rudolf is largely worthless. Instead of relevant scientific experiments, the Rudolf Report contains his theories about how he thinks Iron Blue would have formed in the gas chambers. These theories are not likely to be correct because Rudolf misrepresents the conditions in the gas chambers to make it appear more feasible that Iron Blue would have formed.

In the Rudolf Report, Rudolf repeatedly described the walls of the gas chambers of Crematoria II and III as cool and moist (24) because he believes Prussian Blue is more likely to form in cold and wet conditions (25). However, earlier in the same report, he wrote that between the cellars’ double brick walls there was a layer of tar which was for insulation to keep the water out (26). Rudolf claimed the gas chambers were really morgues and tried to explain the references to heating by arguing that all morgues had heating to protect the corpses from cold temperatures (27).

Rudolf is contradicting himself. First, he says the cellars were morgues and were dry and heated. Then, when considering the likelihood of Iron Blue forming on their walls, the cellars were cold and damp, because the absence of Iron Blue would supposedly suggest they could not have been gas chambers. If the cellars were dry and heated, as Rudolf first maintained, and supported by physical and documentary evidence, then Iron Blue would be less likely to form

Miklos Nyiszli, an Auschwitz survivor who worked as a doctor in the Birkenau crematoria, wrote that after the gas chamber had been ventilated, the Sonderkommando (Jewish prisoners who worked in the gas chambers) hosed down the bodies (28). This would negate Faurisson’s argument about hydrogen cyanide sticking to the corpses. In the process they would have also presumably washed off cyanide accumulating on the walls, again decreasing the likelihood of Iron Blue forming.

Germar Rudolf claims,

“Furthermore, the opinion is occasionally expressed that the homicidal ‘gas chamber’ was sprayed with a water hose after each gassing. This assertion forgets that it would have lasted many hours until the ‘gas chamber’ could have been cleared of bodies (they have to be cremated, which is time-consuming, after all) that the hydrogen cyanide does not merely sit on the surface of the wall, but rather due to its extremely high diffusion capacity, penetrates deeply into the wall within a few hours, and that a water hose would be of no assistance in this regard, quite apart from the fact that such an action would have had the effect of causing the consequently damp walls to absorb even more hydrogen cyanide during the next hypothetical gassing.” (29)

Rudolf is saying they hosed down the gas chamber after all the corpses had been taken out and cremated, leaving more time for the Iron Blue reaction to occur. However, Nyiszli wrote that hosing down the bodies was the first thing they did when they entered the gas chamber, which suggests there would not have been time for the reaction to take place. Rudolf is misrepresenting the evidence to make it appear more likely that Iron Blue should have formed, when an accurate reading of the historical evidence suggests it was less likely.

The amount of Zyklon B used in the gas chambers

Rudolf and other revisionists exaggerate the amount of Zyklon B which the gas chambers would have used, because they believe the more Zyklon B was used, the more likely it is that Iron Blue would have formed. They also want to make the gassings sound too impractical and difficult.

In his report, Germar Rudolf calculated that to reach a concentration of at least 3,000 ppm of hydrogen cyanide in five minutes, 15 kg of Zyklon B would be needed. Zyklon B releases 10% of its gas in the first five minutes. In a crowded gas chamber he claimed they would need at least 20 one kg tins of Zyklon. (30) This conjures up absurd images of the SS pouring 20 tins of Zyklon B into the gas chambers every time they used them.

Rudolf’s calculations are dependent on his assumption that “there was obviously no appliance to distribute the gas quickly over the entire room.” (31) He claims there were not four holes in the gas chamber roof to introduce the Zyklon B and distribute it evenly, so 20 tins would have been needed to give off enough hydrogen cyanide to reach 3000 ppm throughout the gas chamber from one point in five minutes. Rudolf and other revisionists are wrong and there were holes in the roof to drop the Zyklon B in, so it could be distributed evenly (32). The gas could have been distributed evenly and more quickly, so nowhere near 20 cans were needed.

Another revisionist Carlos Porter goes further and claims, “To kill 2000 people in 2 minutes would probably require a ton of pure cyanide.” (33) A 1 kg tin of Zyklon B contains 200 grams of hydrogen cyanide gas (34). A metric ton of hydrogen cyanide gas would require 5,000 tins of Zyklon B. It would have been easier to kill the Jews with the Zyklon B by dropping it on them.

In the original Leuchter Report, Leuchter claimed that the same amount of gas (3,200 ppm) would have been used in the delousing chambers and the gas chambers (35). However, he also wrote that “a concentration of hydrogen cyanide in an amount of 300 ppm in air is rapidly fatal” (36). During the Zundel trial, Leuchter admitted a gas chamber did not need to use the same amount of gas as a delousing chamber. He agreed that 300 ppm of hydrogen cyanide would kill people in about ten to fifteen minutes (37).

As already mentioned, one of the goals of American gas chambers is to kill the prisoner as quickly and as humanely as possible. Hence, they used ten times the necessary amount. On the other hand, the SS did not care if the Jews suffered for an extra few minutes before they died.

In “Technical Aspects of the Holocaust: Cyanide, Zyklon-B and Mass Murder”, Brian Harmon calculated how many people could have been killed using Zyklon B in the Birkenau gas chambers. A gas chamber, which was 210 metres square and 2.5 metres high, would have a volume of 525 cubic metres. At 4 people per square metre, 840 people would fit into the gas chamber. If each person had a volume of .081 cubic metres, there would be 456.96 cubic metes free. 300 ppm of hydrogen cyanide is lethal to humans. Only 176.7 g of hydrogen cyanide is needed to reach a concentration of 300 ppm in 456.96 cubic metres. A can of Zyklon B contained 200g. If five cans, making 1 kg of hydrogen cyanide, were poured in, only 1.76% of hydrogen cyanide would need to evaporate to reach lethal levels in ten minutes. If the four Birkenau gas chambers each containing 840 people, were used once a day for 18 months from May 1943 to November 1944, 1,841,280 Jews could have been gassed, more than the most reliable estimates that 1.1 million Jews were gassed in Auschwitz (38).

Some critics of revisionism believe that more Zyklon B was used in the gas chambers than in the delousing chambers. Jean Claude Pressac suggested the gas chambers used 12 to 20 grams of HCN per cubic metre (39). 20 grams per cubic metre works out at about 18,100 ppm (40). Pressac believed that the crucial factor in the formation of Iron Blue was not so much the amount of hydrogen cyanide used, but the length of time the walls were exposed to the gas. The occupants of the gas chambers were killed in about five minutes, so the walls of the gas chambers were only exposed to the gas for about ten minutes a day. On the other hand, a delousing session took 12 to 18 hours, during which time the walls were exposed to the gas. (41) Although Zyklon B was originally intended to kill lice, it was apparently more effective at killing people.

Thus, if the gas chambers had been used for ten minutes at a time, then 108 gassings would have been the equivalent of one 18 hour delousing session. If the gas chambers were used for ten minutes once a day (and the rest of the day was spent cremating the corpses) for 18 months (540 days), that would be the equivalent of five delousing sessions. This does not necessarily even mean that the amount of Iron Blue one would expect to find in the gas chambers would be about the same as what one would expect after up to ten delousings. Brian Harmon and Mike Stein have written that “the chemical reactions that make prussian blue are very slow, taking many hours to complete” and “can take upwards of 30 hours.” (42) If the walls of the gas chambers were only exposed to hydrogen cyanide gas for ten minutes at a time, then there was simply no time for Iron Blue to form.

In an article “Some Technical and Chemical Considerations about the ‘Gas Chambers’ of Auschwitz and Birkenau” Rudolf wrote that “chemistry is not the right science to find a definitve answer to the question whether homicidal gassings took place in Auschwitz and Birkenau or not.” (43) If Iron Blue should have formed in the Auschwitz gas chambers, as Leuchter and Rudolf maintained, then surely the absence of any significant amount is scientific proof that there were no gassings. This sounds like a backdown from earlier revisionist claims that Leuchter and Rudolf had proved scientifically that there were no gas chambers in Auschwitz and an admission that their methods were flawed and inadequate.

Conclusion – Holocaust revisionism and freedom of speech

Holocaust revisionists, such as Zundel, Faurisson, Rudolf, Irving and Leuchter, have suffered for their beliefs. Some have even been imprisoned. Holocaust revisionists are wrong and are little more than Nazi apologists, but I still believe they have the right to believe what they want and express their views. Freedom of speech is not free. It comes with the price of having to put up with people who say things we do not like. If we only have freedom of speech for those who say things we like, then we do not really have freedom of speech.

Censorship and imprisoning people for what they say creates a dangerous precedent for the censorship and suppression of other unpopular, dissident and politically incorrect beliefs. It was the sort of thing the Nazis did. The hypocrisy of resorting to Nazi methods to defeat modern Nazi apologists is obvious.

However, the harassment and persecution of Holocaust revisionists is not necessarily proof that what they say is true, as some revisionists apparently think, only that people find it offensive. The Leuchter Report is not suppressed truth, but flawed and incompetent propaganda.



(1) The Leuchter Report, op cit., p 22

(2) Ibid., p 15

(3) The Rudolf Report, op cit., p 252-264

(4)The Leuchter Report, op cit., p 13, 16,17, The Holocaust on Trial, op cit., p 370

(5) Robert Jan van Pelt, The Case for Auschwitz, Indiana University Press, 2002, p 361

(6) Ibid., p 359

(7) Truth Prevails, op cit., p 42-43

(8) The Leuchter Report, op cit., p 22, 30, The Case for Auschwitz, op cit., p 200-201

(9) The Leuchter Report, op cit., p 22

      (10) Truth Prevails, op cit., p 44

(11) Paul Grubach, “The Leuchter Report vindicated: A response to J.C. Pressac’s critique”,

(12) Central Commission for the Investigation of German Crimes in Poland, German Crimes in Poland, Warsaw, 1946, Volume 1, p 87

(13) The Leuchter Report, op cit., p 15

(14) Ibid., p 13-14, 16, 17

(15) Robert Faurisson, “Response to a Paper Historian”,

(16) The Holocaust on Trial, op cit., p 368

(17) The Leuchter Report, op cit., p 15

(18) Germar Rudolf, Auschwitz Lies, Theses and Dissertations Press, Illinois, 2005, p 50-51

(19) Germar Rudolf, Lectures on the Holocaust, Theses and Dissertations Press, Illinois, 2005, p 230-1

(20) The Rudolf Report, op cit., p 152

(21) Ibid., p 266

(22) Ibid., p 255, 267-8

(23) Auschwitz Lies, op cit., p 76

(24) The Rudolf Report, op cit., p 216, 276, 282

(25) Ibid, p 161-2

(26) Ibid, p 94

(27) Ibid, p 109

(28) Miklos Nyiszli, Auschwitz, Granada, London, 1980, p 49

(29) The Rudolf Report, op cit., p 284

(30) Ibid., p 209-210

(31) Richard Green, “Report of Richard J. Green, PhD”,

(32) Daniel Keren, Jamie McCarthy and Harry Mazal, “The Ruins of the Gas Chambers: A Forensic Investigation of Crematoriums at Auschwitz I and Auschwitz-Birkenau”, Holocaust and Genocide
Studies, Vol. 18, No. 1, Spring 2004, p 68-103

(33) Richard Green, “The Chemistry of Auschwitz”,

(34) Brian Harmon, “Technical Aspects of the Holocaust: Cyanide, Zyklon-B and Mass Murder”,

(35) The Leuchter Report, op cit., p 11-12

                  (36) Ibid., p 12

                  (37) The Holocaust on Trial, op cit., p 387

                 (38) “Technical Aspects of the Holocaust”, op cit

        (39)Truth Prevails, op cit., p 36

       (40) “Report of Richard J. Green, PhD”, op cit.

      (41)Truth Prevails, op cit., p 36-37

       (42) “Technical Aspects of the Holocaust”, op cit.

(43) Ernst Gauss (ed), Dissecting the Holocaust, Theses and Dissertations Press, Alabama, 2000, p 370

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s