5.8 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Leuchter report | 3/4 | https://en.wikipedia.org/wiki/Leuchter_report | reference | science, encyclopedia | 2026-05-05T09:22:18.136628+00:00 | kb-cron |
The problem with Prussian blue is that it is by no means a categorical sign of cyanide exposure. One factor necessary in its formation is a very high concentration of cyanide. 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 (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. 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. 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. 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. 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". 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.
==== Polish follow-up investigation ==== In February 1990, Professor Jan Markiewicz, director of The Institute for Forensic Research (IFRC) in Kraków conducted an experiment where iron compounds were excluded. 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, 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. 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.
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. 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, 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. 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). 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.
=== Other criticisms === By order of Heinrich Himmler, the crematoria and gas chambers at Birkenau were destroyed by the SS in order to hide evidence of genocide. 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, 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".
==== Zyklon B ==== 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. It is correct that hydrogen cyanide is explosive, but only at concentrations of 56,000 ppm and above – 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 – again considerably lower than the lower explosion limit.
==== Gas chamber ventilation ==== 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.