Leuchter report

Leuchter's opposition to the possibility of homicidal gassings at Auschwitz relies on residual cyanide remains found in the homicidal gas chambers and delousing chambers at Auschwitz.[3]^: 167 While both facilities were exposed to the same substance (Zyklon B), many of the delousing chambers are stained with an iron based compound known as Prussian blue, which is not apparent in the homicidal gas chambers.[5] It is not only this disparity that Leuchter cites, but accordingly from his samples (which included measurements of it) that he claims he measured much more cyanide in the delousing chambers than in the gas chambers, which he argues is inconsistent between the amounts necessary to kill human beings and lice.[3]^: 167 This argument is often cited by Holocaust deniers, and similar claims are also made by Germar Rudolf.

According to Richard J. Green:

In order for Leuchter or Rudolf to demonstrate the significance of their findings, it is necessary for them to prove the necessity of Prussian blue formation under the conditions that the homicidal gas chambers were operated. Showing that the delousing chambers have Prussian blue and that the homicidal gas chambers do not, proves nothing, if it cannot be shown that conditions in the gas chambers were such as to produce Prussian blue.[5]

In other words, Green states that Leuchter failed to show that Prussian Blue would have been produced in the homicidal gas chambers in the first place—meaning its absence is not in itself proof that no homicidal gassings took place.[6]

Gas chamber in Majdanek concentration camp with blue residue

The problem with Prussian blue is that it is by no means a categorical sign of cyanide exposure.[5] One factor necessary in its formation is a very high concentration of cyanide.[5] In terms of the difference between amounts measured in the delousing chambers and homicidal gas chambers, critics explain that the exact opposite of what deniers claim is true. Insects have a far higher resistance to cyanide than humans, with concentration levels up to 16,000 ppm (parts per million) and an exposure time of more than 20 hours[6] (sometimes as long as 72 hours) being necessary for them to succumb. In contrast, a cyanide concentration of only 300 ppm is fatal to humans in a matter of minutes.[7] This difference is one of the reasons behind the concentration disparity. Another exceedingly sensitive factor by which very small deviances could determine whether Prussian blue may form is pH. pH could be affected by the presence of human beings.[5] Also, while the delousing chambers were left intact, the ruins of the crematoria at Birkenau had been exposed to the elements for over forty years by the time Leuchter collected his samples. This would have severely affected his results, because unlike Prussian blue and other iron based cyanides, cyanide salts are highly soluble in water.[5]

Since the formation of Prussian blue is not an unconditional outcome of exposure to cyanide, it is not a reliable indicator. Leuchter and Rudolf claim to have measured much more cyanide in the delousing chambers than in the homicidal gas chambers, but since they did not discriminate against an unreliable factor, Green maintains that instant bias is introduced into their experiments.[5] Similarly, Rudolf acknowledges that Prussian blue does not always form upon exposure to cyanide and is thus not a reliable marker, yet continues to include the iron compounds in his analysis. Green describe this as "disingenuous".[7] Since a building that contains Prussian blue staining would exhibit much higher levels of detectable cyanides than one without any, Green writes that Leuchter's and Rudolf's measurements reveal nothing more than what is already visible to the naked eye.[5]

In February 1990, Professor Jan Markiewicz, director of The Institute for Forensic Research (IFRC) in Kraków conducted an experiment where iron compounds were excluded.[7] Given that the ruins of the gas chambers at Birkenau have been exposed to a cumulative 35 meters of precipitation based on climatological records since 1945,[8]^{: Introduction} Markiewicz and his team were not optimistic at being able to detect cyanides so many years later; nevertheless, having the legal permission to obtain samples, they collected some from areas as sheltered from the elements as possible.[5]

Leuchter's report stated that the small amounts of cyanide he detected in the ruins of the crematoria are merely the result of fumigation. However the IFRC points out that the control samples they took from living areas which may have been fumigated only once as part of the 1942 typhus epidemic tested negative for cyanide, and that the typhus epidemic occurred before the crematoria at Birkenau even existed.[8]^{: Final Remarks}

The ruins of the Crematorium II gas chamber at Auschwitz-Birkenau.

Accordingly, the IFRC demonstrated that cyanides were present in all of the facilities where it is claimed that they were exposed, i.e. all five crematoria, the cellars of Block 11 and the delousing facilities.[5] Critics state that any attempt to demonstrate that the crematoria could not have functioned as homicidal gas chambers on the basis that they were not exposed to cyanide is unsuccessful, given that its presence in what remains of these facilities is incontrovertible,[6] and write that all of the gas chambers were exposed to cyanide at levels higher than background levels elsewhere in the camp, such as living areas, where no cyanides at all were detected.[5] In addition, tests conducted at Auschwitz in 1945 revealed the presence of cyanides on ventilation grilles found in the ruins of Crematorium II (thus also demonstrating that the Leuchter report was not the first forensic examination of the camp as purported in the title of the London edition).[6] The historian Richard J. Evans argued that due to Leuchter's ignorance of the large disparity between the amounts of cyanide necessary to kill humans and lice, instead of disproving the homicidal use of gas chambers, the small amounts of cyanide which Leuchter detected actually tended to confirm it.[9]

By order of Heinrich Himmler, the crematoria and gas chambers at Birkenau were destroyed by the SS in order to hide evidence of genocide.[10] Nothing more than the bases of Crematoria IV and V can be seen: the floor plans of both facilities are indicated by bricks laid out across the concrete foundations,[11] and Crematoria II and III are in ruins. Professor Robert Jan van Pelt labels Leuchter's comment that the facilities have not changed at all since 1942 or 1941 as "nonsense".[4]

Because hydrogen cyanide is explosive, Leuchter maintained that the gas chambers could never have been operated due to their proximity to the ovens of the crematoria.[3]^: 168 It is correct that hydrogen cyanide is explosive, but only at concentrations of 56,000 ppm and above[12] – over 186 times more than the lethal dose of 300 ppm. Critics estimate conservatively that within 5 to 15 minutes, gas chamber victims were exposed to 450 – 1810 ppmv[7] – again considerably lower than the lower explosion limit.

If Leuchter had gone to the archives, if he had spent time in the archives, he would've found evidence about ventilation systems, evidence about ways to introduce Zyklon B into these buildings, evidence of gas chambers, undressing rooms.

— Robert Jan van Pelt, The Rise and Fall of Fred A. Leuchter[4]

Nazi blueprints of the Crematorium II gas chamber, labeled, Leichenkeller or "corpse cellar". A cross section view of the width of the room shows the ventilation channels that straddle the building along its longitudinal axis, marked Belüftung (aeration) and Entlüftungskanal (de-aeration channel).

Leuchter incorrectly assumed that the gas chambers were not ventilated.[13] The basement gas chambers of Crematoria II and III were mechanically ventilated via motors in the roof space of the main crematorium structure[14] capable of extracting the remaining gas and renewing the air every three to four minutes.[15]

When ventilation was not used such as in Crematoria IV and V (although a ventilation system was later installed in Crematorium V in May 1944[16]), Sonderkommando prisoners wore gas masks when removing the bodies.[11] When presented in court with a document by the chief Auschwitz architect SS-Sturmbannführer Karl Bischoff, Leuchter misconstrued aeration (Belüftung) and ventilation (Entlüftung) as part of the furnace blower systems, when they were actually in reference to the ventilation channels in the walls that straddle the gas chambers.[13] These are visible on blueprints, and can still partly be seen in the ruined east wall of the Crematorium III gas chamber.[13]

Leuchter was also prepared to act as expert witness regarding crematoria ovens despite admitting during cross examination that he had no expert knowledge.[13] Leuchter presented his own estimate of 156 corpses as the total daily incineration capacity of the installations at Auschwitz. During cross-examination, he was presented with a letter written by the Auschwitz Central Construction Office (Auschwitz Zentralbauleitung) of June 28, 1943, from SS-Sturmbannführer Jahrling to SS-Brigadeführer Hans Kammler stating that the five crematoria installations had a collective daily capacity of 4,756 corpses. Leuchter conceded that this was quite different from his own figure, and that he had never seen the document in question before.[13]

A patent application by the makers of the ovens, (both of which were made during the war) and two independent testimonies confirmed the capacity of the crematoria.[13] Because the 4,756 figure is evidence of the Nazis equipping a camp of a maximum of 125,000 prisoners with the facility to cremate 140,000 of them per month. Critics of Leuchter explain that this reveals extermination was the true purpose of Auschwitz: a camp with the capacity to reduce its entire population to ash on a monthly basis was not merely a benign internment camp.[17]

At various times (such as in the summer of 1944 when the crematoria couldn't keep up with the extermination rate), bodies were burnt in open-air pits. Accordingly, the capacity of the crematoria was never a limiting factor, and the pits yielded practically no limit to the number of corpses that could be burnt.[18]