2.01 Disparities in Hydrocyanic Compound Levels
Holocaust deniers often claim that since more hydrocyanic compounds were found in the delousing chambers than in the ruins of the so-called "extermination" chambers at Auschwitz, and the reverse would be true if people were actually gassed there, it is clear that no mass gassings occurred.
But - HCN is far more effective on warm-blooded animals (including humans) than on insects, so the period of exposure to HCN is far longer for delousing clothes than that required for homicidal gassings, and a much lower concentration is necessary to kill people as compared to lice.
A concentration of up to 16,000 ppm (parts per million) is sometimes used, with exposure times of up to 72 hours, to kill insects, but as little as 300 ppm will cause death in humans within fifteen minutes or so.
Breitman offers background information about the development of Zyklon B as a killing device, and provides clear evidence that the Nazis determined the effective Zyklon B concentration through a process of trial and error.
When the difference in the concentration of gas required to kill insects and humans was mentioned in Leuchter's cross-examination in the Zundel trial, Leuchter responded: "I've never killed beetles. I, you know, I don't know. I haven't made computations for killing beetles" - Hardly the response one would expect from an "expert" on the subject...
Because of the relatively small concentrations required to exterminate humans as opposed to lice, and because of the far shorter exposure time required, the HCN in the gas chambers used to kill humans hardly had time to form chemical compounds on the walls.
The gas chambers were not very large (those in Kremas II and III were about 210 square meters), and the Zyklon B was dropped through four openings in the roof, spreading the gas very quickly. These openings are still visible in the ruins of the gas chambers, and rare photographs of them, taken while the camp was in operation, exist, and copies are readily available (Brugioni et al) from the sources noted in Section 6.1, below. Since the concentration used was higher than the lethal one, death was swift. (See picture Krema4.gif Krema IV was above-ground, and the Zyklon B was introduced through clearly visible slits in the walls. See also picture Krema401.gif, which provides a close-up of the wall openings.)
Leuchter's data is further suspect because the delousing chambers where he obtained his samples were left intact by the SS, while the extermination chambers were destroyed. Clearly, their walls were exposed to the elements for forty-five years, which would certainly influence the validity of the samples taken. (The ruins of Krema II are covered with about three feet of water during certain periods of the year, and HCN compounds would eventually dissolve under such conditions. Nonetheless, so many gassings occurred there that some of the compound did remain).
Summarizing, the walls of the extermination gas chambers were in contact with HCN for a much shorter time then those of the delousing chambers, and for the last 45 years were exposed to surroundings which dissolve the compounds, while the delousing rooms were not. Therefore it is obvious that less traces of compounds would remain in them. This debunks the major "amazing discovery" in Leuchter's report, which, in retrospect, wasn't "amazing" at all.
This fact - that all, or most, of the compounds would vanish during 45 years of exposure - is quite clearly stated in the report written by the experts at the Cracow Institute of Forensic Research:
