Newsgroups: alt.revisionism Subject: Prussian Blue: Why the Deniers are Wrong PRUSSIAN BLUE: Why the Holocaust Deniers are Wrong by Brian Harmon and Mike Stein. (c) August 1994 see copyright notice below Since very few cyanide traces have been found in the homicidal gas chambers of Auschwitz-Birkenau, many Holocaust deniers assert that no one was gassed there {1,2}. They claim that if cyanide gassing occurred in these structures, large traces of cyanide would remain complexed with iron as a compound called prussian blue. As proof, they point to the fact that large amounts of prussian blue can be found in the small delousing chambers at Auschwitz; there is even some staining on the exterior walls of these structures. By comparison, the homicidal gas chambers have virtually no staining and relatively weak cyanide traces. The deniers further claim that the exterior staining on the delousing chambers proves that prussian blue does not "weather away" even when exposed to the elements, so that the lesser amounts of prussian blue found in the homicidal chambers cannot be explained by weathering. Therefore, say the deniers, the only logical explanation for the small cyanide traces in the homicidal chambers is that cyanide was never used in them for mass murder in the first place - the traces are merely contamination from the delousing operations a few hundred yards away. _The Leuchter Report_, a document written by the self-proclaimed engineer Fred Leuchter {3}, describes the "scientific" sampling he undertook at Auschwitz which "proves" that cyanide could not have been used in the Kremas and Bunkers I and II, the sites in which people were gassed. Although Leuchter misrepresented his credentials and lied about his experience as an expert of execution hardware, many deniers claim that the report is still scientifically valid. While this sounds plausible at first, when one studies the chemistry, toxicology, and physical mechanisms involved, it becomes clear that this reasoning is not valid. As a minor point, even prussian blue is not eternally stable. It will "weather away" over time, at a rate which depends heavily on the environment. Again, however, this is really not important. The two crucial facts are these: one, the chemical reactions that make prussian blue are very slow, taking many hours to complete. Two, people die quickly from cyanide, and from very small amounts. Lice and other insects, on the other hand, require very long exposure to high concentrations. These two factors explain why there is little prussian blue in the extermination chambers, despite copious staining in rooms used to delouse clothing. This paper will compare the two uses of cyanide in Auschwitz; both its use in delousing and in murder. The formation of prussian blue and its solubility in water will also be discussed. We will also examine the Leuchter Report and dissect Leuchter's methods. It should then be clear why one expects fewer traces of cyanide in the homicidal chambers, and also why the deniers have things exactly backwards. I. The Auschwitz Gas Chambers There were seven gas chambers at Auschwitz: Kremas I - V and Bunkers I and II. Kremas II, III, IV, and V were full time industrial gas chambers, located on the Birkenau complex of Auschwitz. These were destroyed by the fleeing Nazis, and none of these are still standing -- only rubble remains {4}. Thus the rubble and any cyanide complexes on it have been exposed to the elements for the past forty nine years. Bunkers I and II were used while Kremas II-V were under construction, and no trace of them remains either. Krema I was a small gas chamber and was used only for a short time before it was converted into an air raid shelter by August 1944 (maybe earlier) {5}. Out of Auschwitz-Birkenau's seven homicidal gas chambers, only Krema I exists as a complete structure today. The fact that all but one of the Auschwitz-Birkenau gas chambers have been destroyed must be kept in mind. The rubble has been exposed to weathering from the rain and wind, which could carry away traces of cyanide by bulk flow and erosion. More cyanide has undoubtedly been removed by dissolution, as prussian blue is not completely insoluble in water. The delousing chambers were not destroyed, so more traces of many cyanide compounds should be found there. II. The Leuchter Report: Cyanide Traces Were Found in the Gas Chambers. Both the Report of the Forensic Research Institute at Krakow and the Revisionist _Leuchter Report_ found traces of cyanide in the extermination facilities at Auschwitz {6, 7}. In _The Leuchter Report_, from 1.9 to 6.7 mg/Kg of cyanide was found in Krema III, 1.1 to 7.9 mg/Kg in Krema I, 1.4 to 2.3 mg/Kg in Krema IV, and 1.7 - 4.4 mg/Kg in Krema V. These low numbers could have been false artifacts of the measurement processes rather than any real signal. To test this, Leuchter tested a sample of gasket material taken from an unrelated building in the camp. If the cyanide traces in the rubble of homicidal gas chambers were a false signal or if the entire camp was contaminated with cyanide, this gasket material should give a similar response. Instead, The gasket registered a flat zero rating. Based on Leuchter's control sample, the cyanide detected in the homicidal gas chambers is real. Even sites reduced to rubble have traces of cyanide, while his unrelated gasket sample does not. Unfortunately for Leuchter's poorly executed report, any conclusions taken from Leuchter's data are limited by the report's poor design. He took only two control samples: a negative control that should generate no cyanide reading (the gasket material), and one positive control that would generate a very high one (a sample from a delousing room stained with prussian blue). Had he taken more control samples from unrelated parts of the camp, he would have some idea of what the normal cyanide levels were and compare that to his findings. As he did not, he could not possibly interpret his results in an intelligent fashion. Yet another worry is the lack of detail Leuchter gave about his sampling technique. Without such information, one cannot review how Leuchter took samples and whether he was biased in choosing which areas of a given building to take samples from. One must wonder why Leuchter was so careless if he was truly a qualified engineer. Leuchter's conclusions are even more suspect. First, he asserts that cyanide found in the gas chamber's remains are so close to the instrument's detection limit (1 ppm) that they are effectively zero. He does not provide his reasons for this conclusion. He also ignores the baseline zero reading an unrelated sample of gasket material gave him. If his results from the homicidal gas chambers are too low to measure, one must wonder why his negative control did not provide a similar result. His biggest error, however, is his assumption that more Zyklon must be used to kill people than delouse clothing {8}: "One would have expected higher cyanide detection in the samples taken from the alleged [sic] gas chambers (because of the greater amount of gassed allegedly used there) than found in the [positive] control sample. Since the contrary is true, one must conclude that these facilities were not execution gas chambers, when coupled with all the other evidence gained on inspection." His conclusion was based on an assumption that far larger amounts of Zyklon B were used in the gas chambers -- an assumption he did not verify with facts. He ignored available information about prussian blue formation, its solubility, and even the actual operation of gas chambers at Auschwitz. His erroneous assumptions and faulty reasoning rendered his report and his data useless. Despite all of Leuchter's bungling, one is left with the nagging problem of why are only minute traces of cyanide found in the rubble of Birkenau's Kremas while much larger amounts are found in the delousing chambers. Despite what may seem to be commonsense logic, these minute traces are to be expected in these chambers, and are consistent with the historical record. We want to emphasize that cyanide traces were found in the remains of Birkenau's extermination facilities, proving that cyanide was used there. Therefore, any speculations about whether or not Zyklon-B could be used for mass murder are purely academic. The traces were there, so cyanide was most certainly used in these rooms. III. Prussian Blue: What is it? Prussian blue is a sparingly soluble salt made of three molecules of iron (II) hexacyanate ion bound to four molecules of iron (III) {9}. The complex can be formed under acidic conditions with a solution of FeSO4 and cyanide ion: Fe+2 + 6CN-1 ----> [Fe(CN)6]-4 4Fe+3 + 3[Fe(CN)6]-4 ----> Fe4[Fe(CN)6]3 prussian blue Note that numbers with a + or - sign denote charge, while those without signs are stoichiometric coefficients. The sulfate ion cancels out, as it is not involved in the reaction. The cyanide ion could be provided by a completely soluble salt like potassium cyanide (KCN) or in equilibrium with the acid form (HCN). Note that the counter ions for cyanide (K+ or H+) will drop out of the equation as well. Prussian blue is not very soluble, with a calculated solubility constant of Ka = 10^-84.5 {10}. Its solubility is highly pH dependent, and it is least soluble at a moderately acidic pH of about 2 - 6 units. It becomes increasingly soluble above a pH of 4.0 {11}. IV. Kinetics of Iron (II) Hexacyanate Formation. Iron (II) hexacyanate is a precursor for prussian blue formation, and the complex will not form without it. It forms in a stepwise fashion, meaning that cyanide ions become complexed to the iron one at a time: Iron (II) Hexacyanate Formation Fe+2 + CN-1 ---> FeCN+1 FeCN+1 + CN-1 ----> Fe(CN)2 Fe(CN)2 + CN-1 ---> [Fe(CN)3]-1 [Fe(CN)3]-1 + CN-1 -----> [Fe(CN)4]-2 [Fe(CN)4]-2 + CN-1 -----> [Fe(CN)5]-3 [Fe(CN)5]-3 + CN-1 -----> [Fe(CN)6]-4 Note that the final product of this reaction is not prussian blue, it is merely the water soluble iron-cyanide complex that combines with more iron to form prussian blue. This product is absolutely required to make prussian blue. This last step is very slow and determines the overall reaction rate {12}. It is so slow that the reaction to produce iron (II) hexacyanate can take upwards of 30 hours to complete when FeSO4*7H20 and KCN are mixed together {13}. Since the production of prussian blue depends on iron (II) hexacyanate, prussian blue formation will be equally slow. This means that a very short time of exposure to cyanide will not produce very much prussian blue at all. Relating this to the gas chambers at Auschwitz, the small amounts of prussian blue in extermination facilities can be easily explained. According to the testimonies of Hans Stark {14}, Auschwitz Commandant Rudolph Ho"ss {15}, and former inmate Marie-Claude Vaillant-Couturier {16}, it would take around one half hour to complete the gassing process and begin ventilation of the chamber. Based on this testimony, it would seem reasonable that very little prussian blue would accrete on the walls of homicidal gas chambers, given the very slow rate of formation and the very short gassing times at Auschwitz. Thirty minutes is not enough to time to produce much [Fe(CN)6]-4, as this reaction takes many hours. Delousing chambers are a different matter. It takes a very long time and a very high concentration to kill insects such as lice with cyanide. Insects often need cyanide concentrations as high as 4600 ppm to kill, while humans need barely 300 ppm {17}. Also, the usage manual from Zyklon's manufacturer, Degesch discusses fumigation times of 16 hours or more, and a minimum of six hours if it is very warm {18}. Given the higher concentrations of cyanide plus much longer (32 times!) gassing times compared to homicidal gassings, significant amounts of [Fe(CN)6]-4 would have time to form, thus leading to the production of large deposits prussian blue in the delousing chambers. Not only was delousing a much longer process, it was done much more often. Jean-Claude Pressac's _Technique and Operation of the Auschwitz Gas Chambers_ compared homicidal gassings with delousing process {19}: "A hydrocyanic gas concentration of 0.3 g/m3 (lethal dose) is immediately fatal for man, while in order to destroy lice a concentration of 5 g/m3 applied for at least two hours is necessary. If this concentration is maintained for 6 hours, all insects are destroyed [source: Degesch]. In Birkenau, the quantity poured into the homicidal gas chambers was forty times the lethal dose (12 g/m3) which killed without fail one thousand people in less than five minutes. [..] The contact time for the hydrocyanic acid with the walls of the homicidal gas chambers never exceeded about ten minutes per day at a temperature below 30 degrees Celsius. In the clothing delousing gas chambers a minimum concentration of 5 g/m3 was used during several cycles per day, the duration of the cycle varying according to the contact time chosen. This hydrocyanic saturation for 12 to 18 hours a day was reinforced by the heat given off by stoves (situated in the chamber) providing a temperature of 30 degrees Celsius. The walls were impregnated with warm hydrocyanic acid for at least 12 hours a day, which was to bring about in situ the formation of a dye, "Prussian blue" or potassium iron (III) hexacyanoferrate (II), whose composition varied according to the conditions of formation." While the execution gas chambers used a higher concentration of Zyklon B, the longer exposure time and heating led to the formation of prussian blue. Pressac goes on to say that the blue color was not visible immediately after the war, but now allows a very easy and foolproof way to distinguish between delousing chambers that have the blue stains, and homicidal ones which do not. Besides the common individual's lack of knowledge of the difference in time and concentration of cyanide between delousing and homicide, another point the deniers count on to create confusion is the nature of "mass gassing." It conjures up the notion of an assembly line, people tossed into the chambers every hour on the hour. However, this was not really the case. Of the over one million people that are believed to have died in Auschwitz-Birkenau, not all of these were gassed. Starvation, overwork, and disease from the inhumane conditions may well have killed more than gas, although the deliberate imposition of these conditions makes it murder no less than death by bullet or cyanide - both of which also took place. Alter Fajnzylberg was a member of the Sonderkommando who was at Auschwitz-Birkenau and managed to survive from the initial gassings in Krema I through to the liberation. He testified that gassings were normally carried out "several times a week," though at one point in 1944, during the arrival of large numbers of Jews from Hungary, Fajnzylberg noted that "gassings took place daily, and even several times a day."{20} Even at that rate, however, the total time of exposure, and thus the amount of prussian blue that one would expect to form, is far less than the deniers are trying to lead people to believe. We realize that the chemistry may be difficult to follow for the average reader. Those who deny the Holocaust count on this in their claim that mass murder should produce more prussian blue than delousing. However, perhaps a physical analogy common to many people's experience may serve to bring the point home. Imagine two white cotton handkerchiefs. One has a medium-hot iron placed on it for four seconds, then taken away for ten seconds. This process is repeated two hundred times. The other has a very hot iron placed on it continuously for two minutes. The first handkerchief, touched by the iron for a total 800 seconds, shows little if any scorching. The second, exposed for 120 seconds, shows clear scorching. The first handkerchief corresponds to the homicidal gas chambers - brief exposure to low concentration of cyanide followed by time for the effect to dissipate - while the second is an analog of the delousing chambers, long continuous exposure to high concentration. V. Solubility of Prussian Blue As mentioned earlier, prussian blue is a largely insoluble salt -- it does not dissolve readily. However, its solubility is highly dependent on the pH of a solution that dissolves it. The salt is least soluble under acidic conditions, and will precipitate below a pH of about 6. Above a pH of 6, it is more soluble and dissolves almost completely {21}. Even above a pH of 4.0, prussian blue dissolves enough to poison the surrounding soil and ground water with soluble iron cyanide. This means that prussian blue will weather away, contrary to the claims of Holocaust deniers. Would rain be of the correct pH to dissolve prussian blue? Based upon a study of acid rain {22} in Northern Europe, the pH of rainfall steadily drops from about 5.8 to 5.0 over a twenty year period (1955 - 1975). An average pH level for the past fifty years could then be very roughly estimated at 5.4 units. Given that prussian blue begins to dissolve at a pH of 4.0, and that any prussian blue on Krema II, III, IV, V has been exposed to this rain for almost fifty years, it is surprising that any such traces remain at all. In their report on cyanide traces in the Auschwitz-Birkenau complex, The Polish Institute for Forensic Research at Krakow erroneously claims that prussian blue will dissolve in weak acid {23}. While it will most certainly dissolve in strong acid (pH<0), it is clearly less soluble at a moderately acidic pH from 2 - 4 {24}. Prussian blue is quite soluble in alkali, but even at the relatively acidic pH of 4 (pH <7 is acidic), prussian blue will dissolve enough to contaminate groundwater to hazardous levels {25}. Perhaps this pH region of 4 - 7 is what they mean, as many weak acids have pKa's in this region. Regardless of the Institute's error, they are correct in surmising that very little, if any traces of cyanide would be found in the homicidal gas chambers at Auschwitz. Besides the chemical mechanism of dissolution, prussian blue exposed to the elements is subject to the physical mechanism of erosion. Any compound which formed on the surface, would be liable to break away in minute particles over time due to the physical impact of rain and wind-blown dust. However, some of the compound infiltrates into the porous brick, and becomes protected by its hardness from this effect. Thus we see long-lasting stains even on some outside surfaces of the delousing chambers - though these surfaces too will have less prussian blue relative to what they did fifty years ago. Still, it is important to keep in mind the main point, namely that the overwhelming reason for the small amount of prussian blue in the homicidal chambers is that there was too small a concentration of cyanide allowed to react for too short a time before the room was ventilated. Thus no significant quantity of prussian blue could form in the first place. VI. Summary and Conclusion Prussian blue is a sparingly soluble salt with the chemical formula Fe4[Fe(CN6)]3. It forms rather slowly, and is quite insoluble at acidic pH. It will dissolve readily at pH of 6.0 or above. Other components formed during prussian blue formation would be soluble and be washed away almost if not completely in a short time. Given the very short time of cyanide exposure in the homicidal gas chambers and that prussian blue forms very slowly, it is unlikely that prussian blue could form there in significant amounts. In delousing chambers, with their high concentration of cyanide and long exposure times of many hours, significant amounts of prussian blue would form. As prussian blue is soluble enough to contaminate groundwater with cyanide at a pH above 4.0, and that it is soluble above pH 6.0, one should expect to find even fewer cyanide traces in the rubble of Krema II, III, IV, and V after fifty years of exposure to the elements. Rainfall can be expected to dissolve prussian blue, albeit slowly. Taking all of these factors into account, it is very unlikely that significant cyanide traces would be found in the rubble of Kremas II - V. Surprisingly, cyanide traces were actually found in the homicidal gas chambers, which proves that HCN was used there. Since the Nazis destroyed these facilities while leaving less incriminating structures intact, it becomes clear that their purpose was not benign. The only apparent discrepancy is that much more cyanide is found in rooms used to delouse clothing. However, with a basic understanding of cyanide chemistry and toxicology one can readily explain the scarcity of prussian blue in the extermination gas chambers despite its prevalence in the delousing facilities. Appendix i. Copyright Notice (c) Brian Harmon and Mike Stein, 1994. This document may be distributed freely as long as credit is given to the authors. This text may not be modified in any way. Sources quoted in this text are copyrighted by the original publishers or authors. ii. Acknowledgements We would like to thank Ken McVay, whose archives and personal assistance have been of great help to us. Ken McVay maintains a large archive of material on the Holocaust and various aspects of Holocaust denial. These files can be accessed by anonymous ftp at http://nizkor.org/ftp.cgi, and via the World Wide Web at http://nizkor.org. [URLs updated 12/25/2005 knm] iv. Quote From Polish Institute For Forensic Research Here is the section from the Polish Institute that makes reference to prussian blue dissolving in acid: ---------------------------------------------------------- INSTITUTE OF FORENSIC RESEARCH In the name of Prof. Dr. Jan Sehn, Krakow Division of Forensic Toxicology Krakow, 24 Sept. 1990 Westerplatte 9 / Code 31-033 Tel. 505-44, 592-24, 287-50 Telex 0325213 eksad ... The hydrocyanic acid (HCN) that is released from the Zyklon B preparation is a liquid with a boiling point of about 27 degrees Celsius. It has an acidic character, and therefore forms compounds with metallic salts, which are known as cyanides. The salts of alkaline metals (such as sodium and potassium) are water soluble. Hydrocyanic acid is a very weak acid, and accordingly its salts dissolve easily in stronger acids. Even carbonic acid, which is formed as a reaction of carbon dioxide with water, will dissolve ferro-cyanide. Stronger acids, such as sulfuric acids, easily dissolve the cyanides. The compounds of cyanide ions with heavy metals are longer lasting. This includes the already mentioned Prussian blue, although this will also slowly ^^^^^^^ ^^^^^^^^ ^^^^^^^^ ^^^^^^^^^ ^^^^^^^^^ dissolve in an acidic environment. ^^^^^^^^ ^^^^^^^^^^^^ ^^^^^^^^^^^^ Therefore, one can hardly assume that traces of cyanic compounds could still be detected in construction materials (plaster, brick) after 45 years, after being subjected to the weather and the elements (rain, acid oxides, especially sulfuric and nitrogen oxides). More reliable would be the analysis of wall plaster [samples] from closed rooms which were not subject to weather and the elements (including acid rain). The discovery of hydrocyanic acid compounds in samples of material which had been subject to the elements can only be accidental. ---------------------------------------------------------- While prussian blue will dissolve in a somewhat acidic environment, increasing acid makes it less soluble, contrary to what the Polish report implies. v. Endnotes 1) Leuchter, Fred. _The Leuchter Report: The End of a Myth_. Samisdat Publishers, (c) 1998. p 17. 2) The Institute of Forensic Research Report is cited in The Summer 1991 issue of the _Journal For Historical Review_ (Institute for Historical Review: Torrance, CA) 3) Leuchter, p 1. 4) Brugioni, Dino and Poirier, Robert. _The Holocaust Revisited: A Retrospective Analysis of the Auschwitz-Birkenau Extermination Complex_. (Washington D.C.: Central Intelligence Agency). (c) Feb. 1979, pp 13-14 5) ibid, p 5. 6) Institute of Forensic Research Report, JHR, summer '91 7) Leuchter, p 17. 8) Leuchter, p 11. 9) Sharpe, A. G. _The Chemistry of Cyano Complexes of the Transition Metals_. (Academic Press: New York, London, San Francisco) (c) 1976, p 122. 10) Meeussen, Johannes C. L., Meindert Keizer G., van Riemsdijk, Willem H., and de Haan, Frans A. M. "Dissolution Behavior of Iron Cyanide (Prussian Blue) in Contaminated Soils" _Environmental Science and Technology_, vol 26, no 9, 1992. p 1834 (figure). 11) Meeussen, p 1832. 12) Sharpe, 104. 13) ibid, p 104. 14) _"The Good Old Days": The Holocaust as Seen by Its Perpetrators and Bystanders_. ed by Ernst Klee, Willi Dressen, and Volker Reiss. English translation of "Die Scho"ne Zeit". (New York: The Free Press, div. of MacMillan, Inc.) (c) 1991., p 255. 15) _"The Good Old Days"_, p 272. 16) _Documents on the Holocaust: Selected Sources on the Destruction of the Jews of Germany and Austria, Poland, and the Soviet Union_. ed. by Yitzhak Arad, Yisrael Gutman, and Abraham Margaliot. (Jerusalem: Yad Veshem) (c) 1981, p358. 17) Hansen, James D., Hara, Arnold H., Chan, Harvey T., and Tenbrik, Victoria L. "Efficacy of Hydrogen Cyanide Fumigation as a Treatment for Pests of Hawaiian Cut Flowers and Foliage After Harvest" _Journal of Economic Entomology_, vol 84, no 2, p 534. 18) Nuremburg Document NI-9912, the Degesch Manual on how to use Zyklon properly. Both German and English versions were obtained from: Mendelsohn, John and Detwiler, Donald S. _The Holocaust: Selected Documents in Eighteen Volumes._ "Volume 12: The 'Final Solution' in the Extermination Camps and the Aftermath" (New York: Garland Publishing) c. 1982, p 137. 19) Pressac, Jean-Claude. _Auschwitz: Techniques and Operation of the Gas Chambers_ (English edition) (New York: Beate Klarsfeld Foundation) c. 1989, p 53. [The translation quoted in this document is by Michael Stein, made directly from the photographic facsimile of the original French statement. It is slightly more literal than the translation appearing in the English edition of Pressac.] 20) ibid., p 124-125. 21) Meeussen, p 1832, 1835. 22) Ode'n, Svante. "The Acidity Problem -- An Outline of Concepts". _Water, Air and Soil Pollution_ vol 6, 1976. p 142. 23) Institute of Forensic Research Report, _JHR_, summer '91 24) Meeussen, p 1835. 25) ibid, p 1832.
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