V. REVISIONIST SCIENCE 2 (Zyklon B and Ventillation)
1. The suitability of Zyklon B as an agent of mass killing
Odd that the Negationists would even make this half-hearted attempt to question the suitability of Zyklon B as a murder weapon, given that they already acknowledged in their opening statement that...
2) Zyklon B as a commercial product developed by German industry during the 1920s for pesticide is likewise agreed to as verified by the Negationist team, along with its capability as containing HCN [= hydrocyanic acid] for homicide; likewise that Zyklon B was ordered, bought, and received by KL authorized personnel at various times during the operation of these camps while under German control.
I suppose they will claim they are not disputing its capability as such, but its capability as the evidence shows it to have been used. In which case their claims must be tested against whether they have any real sense of what that evidence is.
The Negationists appear to approach the problem of Zyklon B from two different angles, the first relating to the properties of the poison in comparison to what is reported by eyewitnesses, and the second to the problems involved in ventilating the gas chambers. Let us look at both of these objections.
The NT cites web page about a study of the humaneness of using HCN in capital punishment. The core of the study finds that in 113 cases of state imposed death by HCN, the length of time the condemned were conscious and in pain was much longer than previously thought. The average time to death in these cases was 9.3 minutes.
Hydrocyanic acid is used as a means of execution in many American states, including Arizona, the last in 1999. It took 18 minutes for the last condemned man to clinically die. Opponents of capital punishment claim that death by lethal gas takes too long. They have cited data to determine how long incapacitation occurs from the time the gas "hits the face." In an execution database recorded by physicians and other observers, survival time was nine minutes to "certain unconsciousness," and "apparent unconsciousness" took as long as five minutes to occur.
Based on this information they attempt to mount another attack on testimonial evidence.
Empirical evidence therefore contradicts Sonderkommano testimony that says that death for some was instantaneous as soon as the Zyklon was poured in, with the other screams dying away in a few minutes, a powerful fan then switched on and the gaschamber cleared of corpses.
Once again, as with the quote cited in our introduction, the Negationist team, having ignored completely our actual argument, are spuriously declaring, on their own authority, what our case must consist of and what positions we are required to defend. Yet we fail to see how the precise amount of time it takes for HCN to kill - or whether every anonymous Sonderkommando witness was precisely accurate in their assessment of this point - has any bearing on our position on the resolution or our argument defending it. In any case, the Veritas team is left to wonder which Sonderkommano testimony the Negationists cherry-picked to back this categorical statement. As usual, our opponents make a claim, but oddly provide no support for it.
Let's see, then, whether the "empirical evidence" really does contradict the normative case, let alone the balance of Sonderkommando testimony. We will start by looking at some of the testimonies about gassing time, both from Sonderkommandos and Nazi perpetrators, to determine if they are contradicted by the website material presented.
"The process could be observed through the peep hole in the door. Those who were standing next to the air shaft were killed immediately. I can state that about one-third died immediately. The remainder staggered about and began to scream and struggle for air. The screaming, however, soon changed to gasping and in a few moments everyone lay still. After twenty minutes at the most, no movement could be detected. The time required for the gas to take effect varied according to weather conditions and depended on whether it was damp or dry, cold or warm. It also depended on the quality of the gas, which was never exactly the same, and on the composition of the transports, which might contain a high proportion of healthy Jews, or the old and sick, or children. The victims became unconscious after a few minutes, according to the distance from the air shaft. Those who screamed and those who were old, sick, or weak, or the small children died quicker than those who were healthy or young."
"At another, later gassing -- also in autumn 1941 -- Grabner* ordered me to pour Zyklon B into the opening because only one medical orderly had shown up. During a gassing Zyklon B had to be poured through both openings of the gas-chamber room at the same time. This gassing was also a transport of 200-250 Jews, once again men, women and children. As the Zyklon B -- as already mentioned -- was in granular form, it trickled down over the people as it was being poured in. They then started to cry out terribly for they now knew what was happening to them. I did not look through the opening because it had to be closed as soon as the Zyklon B had been poured in. After a few minutes there was silence. After some time had passed, it may have been ten to fifteen minutes, the gas chamber was opened. The dead lay higgledy-piggedly all over the place. It was a dreadful sight."
"Meanwhile Grabner gave a sign to the driver of a lorry, which had stopped close to the crematorium. The driver started the engine and its deafening noise was louder than the death cries of the hundreds of people inside, being gassed to death. Grabner looked with the interest of a scientist at the second hand of his wrist watch. Cyclon acted swiftly. It consists of hydrocyanic acid in solid form. As soon as the tin was emptied, the prussic acid escaped from the granules. One of the men, who participated in the bestial gassing, could not refrain from lifting, for a fraction of a second, the cover of one of the vents and from spitting into the hall. Some two minutes later the screams became less loud and only an indistinct groaning was heard. The majority of the victims had already lost consciousness. Two minutes more and Grabner stopped looking at his watch. It was over. There was complete silence. The lorry had driven away. The Guards were called off, and the cleaning squad started to sort out the clothes, so tidily put down in the yard of the crematorium. Busy SS-men and civilians working in the camp were again passing the mound, on whose artificial slopes young trees swayed peacefully in the wind. Very few knew what terrible event had taken place there only a few minutes before and what sight the mortuary below the greenery would present. Some time later, when the ventilators had extracted the gas, the prisoners working in the crematorium opened the door to the mortuary."
"Having donned his gas mask, he lifted the lid of the pipe, which was also made of concrete. He opened one of the cans and poured the contents – a mauve granulated material –into the opening. The granulated substance fell in a lump to the bottom. The gas it produced escaped through the perforations, and within a few seconds filled the room in which the deportees were stacked. Within five minutes everybody was dead... In order to be certain of their business the two gas-butchers waited another five minutes. Then they lighted cigarettes and drove off in their car. They had just killed 3,000 innocents.... Twenty minutes later the electric ventilators were set going in order to evacuate the gas."
Dr. Andre Lettich:
"Then SS-Unterscharfuhrer Moll dropped the gas through a little window. The cries that could be heard were frightening, but after a few moments complete silence reigned. Twenty to twenty-five minutes later the windows and doors were opened to air the room, and the corpses were immediately thrown into ditches, where they were burned."
"Then the door was opened and the people were crowded into the gas chambers which gave the impression that the roof was falling on their heads, as it was so low. With blows from different kinds of sticks they were forced to go in and stay there, because when they realized that they were going to their death they tried to come out again. Finally, they succeeded in locking the doors. One heard cries and shouts and they started to fight against each other, knocking on the walls. This went on for two minutes and then there was complete silence. Five minutes later the doors were opened, but it was quite impossible to go in for another twenty minutes."
"When everybody is inside, the heavy doors are closed. Then there is a short pause, presumably to allow the room temperature to rise to a certain level, after which SS men with gas masks climb onto the roof, open the traps, and shake down a preparation in powder form out of tin cans labeled "CYKLON" "For use against vermin," which is manufactured by a Hamburg concern. It is presumed that this is a "CYANIDE" mixture of some sort which turns into gas at a certain temperature. After three minutes everyone in the chamber is dead."
All the testimony talks about minutes, of varying degrees, for death to occur.
It is clear, then, that our opponents have misrepresented the testimony. We also need to remember that eyewitnesses were merely estimating the amount of time. They were not medical staff recording with a clock and through use of monitoring equipment the progressive stages of consciousness, unconsciousness and finally death. Hoess had no medical way of knowing that those near the "air shaft" were indeed dead "immediately". He merely equated their likely immediate unconsciousness with death. All of the eyewitnesses knew the approximate time the gassing lasted, and that the victims were dead when the gas chamber doors were opened. And the estimates of time given are hardly out of keeping with the 9.3 minute average by the research cited.
Franciszek Piper, Auschwitz historian, has described the process for Crematoria II and III as follows:
[…]When the chamber was full or the entire transport was inside and the personnel had left (two SS noncommissioned officers always stayed until the end), the doors were shut, the bolts were slid into place, and the screws were tightened. On order of the supervising SS doctor (the job was assigned to, among others, Josef Mengele, Hans Konig, and Hans Thilo), the SS disinfectors (Scheinmetz, among others) opened the Zyklon B cans and poured their contents into the vents down the induction shafts inside the chamber.
Within several minutes, 20 at most, all the victims were dead. The time required for the gas to take effect depended on various factors that affected the evaporation of the gas: temperature, humidity, the congestion inside the chamber. Whenever the outside air temperature was higher than the inside temperature, the cool air was extracted by ventilators from the chamber before the gas pellets were poured inside. To speed up the evaporation of the poison gas in winter, iron baskets filled with red-hot coke were brought inside. Some unsuccessful attempts were made to heat the chamber interior with heat from the chimney flues.
Hoess, who personally observed the killing in the gas chambers, described the process:
"It could be observed through the peephole in the door that those who were standing nearest to the induction vents were killed at once. It can be said that about one-third died straightaway. The remainder staggered about and began to scream and struggle for air. The screaming, however, soon changed to the death rattle and in a few minutes all lay still"
About a half hour after the induction of the gas, the ventilation was turned on, the door was opened, and Sonderkommando prisoners wearing gas masks began dragging the corpses out of the chamber. In cases of great congestion, many of the dead were found half-squatting, their skin colored pink with occasional red or green spots. Some foamed at the mouth, others bled from the ears.
In the gas chamber's anteroom, the bodies were relieved of spectacles and artificial limbs, and the women's hair was cut off. Thereupon the corpses were loaded on the elevator platform and lifted to the ground floor. Some of the corpses were dragged directly to the oven area. Others were moved to the corpse storage room opposite the elevator, which also served as a site of executions by shooting. Just before the incineration, Sonderkommando prisoners removed jewellery, which they tossed into a special numbered crate...
[Anatomy of the Auschwitz Death Camp. Indiana University Press, 1998, p. 169-171][emphases ours]
According to Piper, then, the times for death (or the preceding unconsciousness which eyewitnesses might take to be death) were not very different from the NT’s Arizona penitentiary example. What's more, Piper points out that various factors affecting evaporation of the gas influenced the time required for the gas to take effect, such as "temperature, humidity, (and) the congestion inside the chamber", all of which should be taken into account when comparing the duration of gassings at Auschwitz-Birkenau with the 1999 gassing in an Arizona penitentiary the NT tells us about (and regarding which a source reference would be much appreciated), to make sure that we are not comparing apples with oranges. Information would also be required about the concentration of deadly HCN gas in the Arizona execution. The amount reported to have been used at Auschwitz-Birkenau shows a considerable overkill:
[…]Pressac reconstructs a gassing that took place March 13, 1943:
That same night, 1,492 women, children, and old people, selected from a convoy of 2,000 Jews from the Krakow ghetto, were killed in the new crematorium. Six kilos of Zyklon B were poured into the stacks that opened into the four grillwork columns implanted between the pillars that supported the ceiling. Within five minutes, all the victims had succumbed.
[emphasis VT] The aeration (8,000 cu m an hour) and deaeration system (same strength) were then started up and, after 15 to 20 minutes, the atmosphere, which had been practically renewed every three to four minutes, was sufficiently pure so that members of the Sonderkommando could enter the stiflingly hot gas chamber. During this first gassing [in the new Krema II gas chamber], the Sonderkommandos wore gas masks as a precaution. The bodies were untangled and dragged to the goods elevator. Hair was clipped, gold teeth pulled out, wedding rings and jewels removed. 23[…]
Richard Green, The Chemistry of Auschwitz
This information is corroborated by the “DIRECTIVES FOR THE USE OF PRUSSIC ACID (ZYKLON) FOR THE DESTRUCTION OF VERMIN (DISINFESTATION)” (which we will hereafter refer to as the “Instructions”), introduced at the Nuremberg Trials as Document DOC. NO. NI-9912 and scanned in, together with the respective translation (which is transcribed in the Documents of Debate section), on Carlos Porter’s website starting at the link http://www.cwporter.com/pg387.htm
. Here is what it has to say about the properties of Zyklon B and its application for fumigation:
[…]I. Properties of prussic acid (hydrocyanic acid)
Prussic acid is a gas which is generated by evaporation
Boiling point: 25 degree centigrade[correct transcription of German original accordingly]
Freezing point: - 15 degrees centigrade
Specific gravity: 0.69 [correct transcription of German original accordingly]
Steam density: 0.97 (Air = 1.0)
The liquid evaporates easily.
Liquid: transparent, colourless.
Smell: Peculiar, repulsively sweet
Toxic effects on warm-blooded animals
Since prussic acid has practically no indicative irritant effect, it is highly toxic and very dangerous. Prussic acid is one of the most powerful poisons. 1 mg per kg of body weight is sufficient to kill a human being. Women and children are generally more susceptible than men.[…]
If exposure to 1 mg per kg of body weight was sufficient to kill a human being, then 70 mg were sufficient to kill an average male weighing 70 kg. Six kilograms = 6,000 grams = 6,000,000 milligrams, as mentioned in the above-quoted description of a gassing, could thus have killed 85,714 such average males. If all 1,492 people gassed on the occasion described by Pressac had been adult males weighing 70 kg on average, the amount of gas used would thus have been more than 57 times
as high as the minimum amount required to kill them. As the transport consisted of women, children and old people (women and children are “generally more susceptible than men”), the overkill can be expected to have been even higher. The killers clearly took no chances.
Given the described properties of the substance and the amounts of it used for killing, is there anything surprising about eyewitness descriptions according to which people standing next to the introduction shaft, and thus hit by the highest concentration of prussic acid, lost consciousness and died immediately, while those standing further away had to struggle a little longer?
This was also the conclusion reached by a court expert who, at the trial against Johann Paul Kremer before the Landgericht
(County Court) of Münster, West Germany, assessed the dying in the Auschwitz-Birkenau gas chambers in order to determine whether death had been cruel, as this is one of the characteristics by which a homicide is qualified as murder under German law. In its judgment of 29.11.1960, transcribed on the Justiz und NS Verbrechen website of the University of Amsterdam under www1.jur.uva.nl/junsv/Exc...Kremer.htm the LG Münster refers to the expert’s report as follows:
[…]Die Blausäure ist ein ausserordentlich stark und schnell wirkendes Giftgas. Ihre Wirkung besteht darin, dass sie das Atmungsferment okkludiert mit der Folge einer sofortigen Lähmung des Atmungszentrums. Die für den Menschen tödliche Dosis liegt bei 1 mg/kg Körpergewicht. Bei ausreichender Gaskonzentration tritt der Tod schlagartig und ohne dass Schmerz empfunden wird ein. Die zuletzt genannten Feststellungen beruhen auf dem überzeugenden Gutachten des Sachverständigen Prof.Dr.Dr.h.c. B.
Nach dem Einwerfen des Zyklon B in die Gaskammern wurden die Menschen, die in der unmittelbaren Nähe des Einwurfschachtes standen, sofort getötet. Diejenigen hingegen, die weit von dem Einwurfschacht entfernt standen, kämpften noch minutenlang um ihr Leben. Sie mussten, bevor sie selbst tot zusammenbrachen, den verzweifelten Todeskampf ihrer Leidensgenossen miterleben. Die draussen vor den Gaskammern Stehenden hörten deutlich die Geräusche dieses Todeskampfes. Der Angeklagte selbst hat bekundet: "Die Menschen schrien einige Minuten und kämpften um ihr Leben."[…]
"... Prussic acid is an extraordinarily strong and fast-working poison gas. Its effect consists in occluding the breathing ferment, which leads to an immediate paralysis of the respiration center. The dose lethal for human beings is 1mg per kg of body weight. If the gas concentration is sufficiently high, death occurs instantly and painlessly. The findings last mentioned are based on the convincing report of expert Prof.Dr.Dr.h.c. B.
"After the Zyklon B was thrown into the gas chambers, the people standing in the immediate proximity of the introduction shaft were killed immediately. Those standing further away from the introduction shaft, however, still struggled for their lives over a period of minutes. Before they dropped dead themselves, they had to witness the desperate death struggle of their companions in suffering. Those standing outside the gas chambers clearly heard the noise of this death struggle. The accused himself stated that: "The people screamed for some minutes and struggled for their lives."
So when the NT conclude that - "empirical evidence therefore contradicts Sonderkommano testimony that says that death for some was instantaneous as soon as the Zyklon was poured in, with the other screams dying away in a few minutes, a powerful fan then switched on and the gaschamber cleared of corpses"
- the questions that naturally arise are: what
Sonderkommano testimony is contradicted by what
empirical evidence? As demonstrated above, the NT have shown us no empirical evidence that would support this bold assertion of theirs.
NT: […]Various sizes of Zyklon B cans were made depending on the size of the area that needed gassing. Zyklon B was thus practically ideal for fumigation of buildings because it released the deadly gas slowly and the residue was completely inert once it had given up its HCN and could merely be swept away after the area had been ventilated.
The contention is that the fumigant Zyklon B released its deadly hydrocyanic acid “slowly”. But as we recall from the "Instructions" document, quoted above, "The liquid evaporates easily."
To quote further from the same document:
VIII. Preparation for fumigation
8. Open the cans and pour out their contents. The contents are to be spread thinly so that the Zyklon can evaporate quickly and the necessary density of the gas can be achieved as soon as possible. […][emphases ours]
This suggests that Zyklon B evaporates easily
and that the necessary density for fumigation can be achieved within a short time. This is not surprising. The toxic agent in Zyklon B was hydrogen cyanide (HCN), also known as hydrocyanic acid, prussic acid or Blausäure, in German. In his online article The Chemistry of Auschwitz
, Dr. Richard Green describes the properties of this substance as follows:
[…]HCN is a high vapor pressure liquid; the Merck index lists its boiling point as 25.6 degrees Celsius (78.8 degrees Fahrenheit), significantly less than human body temperature. 15 At room temperature (25 d C, 77 d F) the equilibrium vapor pressure of HCN is 750 Torr (760 Torr= 1 atmosphere), corresponding to 987,000 ppm. At 0 C (32 F) it is 260 Torr corresponding to 342,000 ppm. 16 The Merck index warns, "Exposure to 150 ppm for 1/2 to 1 hr may endanger life. Death may result from a few min exposure to 300 ppm"
17 Clearly, it is not necessary to reach equilibrium vapor pressure in order for the fumes of the liquid to be quite deadly.
The boiling point of a liquid is the temperature at which its equilibrium vapor pressure is equal to the pressure of the atmosphere. Below the boiling point the vapor pressure of a liquid can be quite large.
HCN has an extremely high vapor pressure even at very cold temperatures. Anyone who doubts this fact should obtain some diethyl ether, open a small amount, and observe it evaporating. Ether boils at 34.6 Celsius; in other words its boiling point is greater than HCN. 68
This discussion is worthwhile because it shows how the deniers play on the public's relative ignorance on such technical details. The argument, however, is moot because Gerhard Peters, who was the general director of Degesch, the company that sold Zyklon B has written a book on the topic, in which he gives the evaporation times of Zyklon B.
69 Ulrich Roessler translates:
The development of the gas from the Zyklon sets in with great vehemence immediately following the pouring out of it.
The thinner the layer of the disseminated support material the faster will be the development of the gas. Depending on the species of the pests to be controlled, and on the characteristic of the rooms to be gassed, one may choose to reach the maximum of the gas concentration to arise very quickly or more slowly by the thickness of the disseminated layer. Usually, the material will be disseminated in a layer of 1/2 to 1cm thickness, then the greatest part [der grösste Teil] of the HCN will have developed already after half an hour at normal temperature. [i.e. 20 degree C]
Roessler comments further:
Now, der gröste Teil der Blausäure is by no means only 50% - it means rather nearly all of the HCN.
Even at -10 C Peters states that the evaporation is essentially complete in 1 hour with an upper bound for complete evaporation of 2 hours. 72[....] http://www.holocaust-history.org/auschwitz/chemistry/
The above clearly shows that:
a) With a boiling point of slightly above 25 degrees centigrade, Zyklon B would boil and thus evaporate immediately at that temperature, which corresponds to amenable room temperature.
b) Even when not reaching the boiling point, i.e. at lower temperatures, Zyklon B would evaporate rather quickly to the point of killing within a few minutes (at 300 ppm, way below equilibrium vapor pressure, see above).
c) Even at a temperature slightly below its boiling point (20 degrees centigrade, according to Peters) it would have almost wholly developed after half an hour.
The NT’s canard about the deadly hydro-cyanic acid being released “slowly” by Zyklon B has thus been shown for what it is.
NT: Hydrogen cyanide penetrated well and was extremely deadly to lice, their nits, and other vermin like fleas, ticks and rodents, that all carry and spread disease germs.
What the NT don’t tell us is that, unlike human beings, who after exposure to even low amounts of HCN (1 mg per kg of body weight, see the above quote from the “Instructions”) would die rather quickly (a severely poisoned person would “collapse suddenly and faint”, according to the “Instructions”, after which death would come about unless immediate artificial respiration and special medication were provided), insects usually took 16 or more hours to die, as the following excerpt from the “Instructions” shows:
[…]Time needed to take effect: 16 hours, unless there are special circumstances such as closed-in type of building, which requires less time. If the weather is warm it is possible to reduce this to a minimum of 6 hours.
The period is to be extended to at least 32 hours if the temperature is below 5 deg. Cent.
The strength and time as above are to be applied in the case of: bugs, lies, fleas etc., with egg, larves and chrysalia.
For clothes-moths: temperature above 10 deg. Cent. 16 g per cbm and 24 hours to take effect.
For flour-moths: same as for bugs.[…]
NT: Instead we get accounts of corporals chiseling holes in the roofs of basements or dumping insecticide through attic vents, not to fumigate but to exterminate.
The only account of “corporals chiseling holes in the roofs of basements” we know of is the following, contained in the above-quoted excerpt from Constantine FitzGibbon’s translation of Höss’ autobiography: "[…]I have a clearer recollection of the gassing of nine hundred Russians which took place shortly afterwards in the old crematorium, since the use of Block 11 for this purpose caused too much trouble. While the transport was detraining, holes were pierced in the earth and concrete ceiling of the mortuary.[…]"
This account clearly referred to an improvised procedure in an existing installation, the old crematorium of the Auschwitz main camp. We look forward to our esteemed opponents showing us a description of “chiseling holes in the roof of basements” regarding the Birkenau crematoria built in 1942/43. Anyway, such “chiseling” would not necessarily reduce the efficiency of the killing process – even though it would, of course, have been a less elegant solution from the point of view of engineering, assuming that, as our opponents would like to believe, “one could expect” the killers to have been concerned about such finesses.
NT: […]We have stories where instant death occurs and minutes later special-teams go in to pull out the bodies to be further violated and cremated.[…]
Do we, dear opponents? The please show us one
. As we have seen, the eyewitness testimonials we posted here and in the Documents of Debate section do not suggest such an “instant death” and “minutes later” sequence.
Victim cartoons prove it!
Warning, graphic image by David Olere!
Calling David Olére’s drawings (which contain details coincident with independent eyewitness and documentary evidence) “Victim’s cartoons” says much about what goes on in our opponents’ minds but little else. And, as observed before, their claim that his drawings are invoked as “the” proof is all the more grotesque considering that Olére was not even mentioned in our Opening Statement.
NT: With our homicidal gas chambers, as alleged, there is no provision to heat the Zyklon B other than body heat inside a crowded death chamber, nor to recirculate the air. Incredibly, this means that even long after the victims are dead the granules are still releasing their HCN!
That this is nonsense already becomes apparent from the evaporation times of Zyklon B mentioned above. The above-quoted passages on the properties of Zyklon B, especially its boiling point, suggest that the cumulated body heat of hundreds of bodies closely pressed together was more than enough to provide for quick evaporation. The depositions of two eyewitnesses (Dr. André Lettich and Szlama Dragon) expressly mention a waiting period between the closing of the gas chamber doors and the introduction of the poison. Artificial heating also seems to have been applied, however, when the outside temperature was a little colder.
Furthermore there was a procedure for extracting the granules after they had released enough deadly HCN into the gas chamber, described as follows by Jamie McCarthy and Mark Van Alstine in their online article, Zyklon Introduction Columns
, http://www.holocaust-history.org/auschw ... o-columns/
[...] At Auschwitz-Birkenau, in the gas chambers of crematoria II and III, Zyklon-B was poured in through holes in the roof. After early experiments with this poison, the camp staff had learned that it was important to allow the pellets of Zyklon to be removed after the victims' death, and also to spread them to increase the speed of outgassing.
The solution to these problems was a wire mesh column, which ran from the floor up through the roof. An SS man, wearing a gas mask and standing on the roof, would pour the pellets into the top of the column and place a wooden cover over it. The pellets fell into an inner wire mesh basket, which held them as they released their poison into the gas chamber.
After the mass murder was complete, the cover was opened, the basket was pulled up, and the Zyklon expelled the remainder of its poison harmlessly into the open air. Meanwhile, the ventilation of the gas chamber and the cremation of the corpses could begin.[…]
NT: We are simply told by van Pelt that a "powerful fan" removed the poison gas in short order.
We are "simply told", then, are we. Naturally, it is in the Negationist team's interest to word this claim in terms that imply that Van Pelt merely made this conclusion up, as they know full well that they have no basis to refute the documentary evidence on which this claim is, in fact, based. Actually the ventilation system of the gas chambers is addressed in detail in The Van Pelt Report, submitted at the Irving-Lipstadt trial and transcribed under http://www.hdot.org/en/trial/defense/van
The Negationists elaborate on this allegedly inadequate ventilation system a few lines down:
NT: The ventilation for the corpse undressing room and the morgue in both of the basements of Kremas II and III was about 9-16 exchanges per hour, certainly not any powerful extraction system.
Another hilariously dishonest sentence, rather akin to someone saying that the temperature in Athens and Oslo today is between 9-24 degrees - technically correct but functionally useless, and highly misleading if you happen to be in either Athens or Oslo. It was only L-keller 1 - the room designated by the Negationists as the "morgue" - in which Zyklon B is alleged to have been used to gas people, and hence it is only the ventilation rate of that room which is of relevance. The only possible reason why the Negationist team would see fit to include the undressing room in their consideration of the ventilation is to justify lowballing us with a range rather than a specific figure. If they wanted to express the same information honestly, they would have said that the ventilation rate was 9 exchanges per hour in the undressing room, and 16 in the "morgue"
. But such a construction would hardly have served their rhetorical purposes, as this contrast is itself of interest, especially when one considers that it reflects a curious revision from the original construction plan. The initial blueprint for a single morgue facility at Birkenau called for L-keller 1 to have only a deaeration motor with a capacity of 4000 cu m/hr, that would have given L-kellers 1 and 2 comparable ventilation rates. The revised version ultimately provided L-keller 1 (the gas chamber) with an 8000 cu m/hr deaeration motor, giving it almost twice the deaeration capacity of L-keller 2 (the undressing room), adding as well an aeration chimney to L-keller 1, making this the only room in the building with it's own aeration as well as deaeration system. These revisions were all made in the spring of 1942, within weeks of the period in which historians of Auschwitz generally agree the decision was made to use Birkenau as a site of mass murder.
"Certainly not any powerful extraction system"? The Negationists simply declare this to be so, and, offering no explanation as to why this would have been inadequate, expect us to take their expertise on the ventilation of gas chambers on faith. But an aeration/deaeration system with a throughput of 8000 m3/hr for a room with a volume of about 500 m3 means that all of the air in L-keller 1 could be circulated by this air extraction system within 4 minutes. According to the witnesses already cited, the SS ran the ventilation system for about 20 minutes before opening the doors to begin extracting the bodies. In other words, all of the air in the room would have been exchanged already five times.
But what of the N-team's objection that
With Zyklon B we need to allow time for the gas to be released; and even when the victims are all dead, unless the carrier material is heated or removed somehow it will slowly continue releasing poison for a long time, thus making ventilation impossible.
Despite the data we have cited, of which the Negationists were evidently unaware, showing that the material was
sufficiently warm and was
removed, what if there were still unavoidable leftover pockets of HCN? Well, look no further than the testimonies of the eyewitnesses for a simple idea as to how to neutralize this possibility, one that would naturally have occurred to those technologically efficient Nazi whiz-kids but that evidently did not occur to the Negationists. According to Miklos Nyiszli, even though the ventilators, "quickly evacuated the gas from the room, but in the crannies between the dead and the cracks of the doors small pockets of it always remained. Even two hours later it caused a suffocating cough. For that reason the Sonderkommando which first moved into the room was equipped with gas masks...." (Auschwitz: A Doctor's Eyewitness Account
Like so many other “Revisionist” canards, the one regarding the ventilation of the gas chambers plays on the readers ignorance and/or gullibility. In his online article Chemistry is not the Science
, Dr. Richard Green writes:
The Sonderkommando were slave laborers: to their SS slavemasters they were expendable. The SS certainly did not have to obey OSHA regulations. They would not be averse to exposing the Sonderkommando to concentrations of approximately 40 ppmv ("slight symptoms after several hours"). Even if the full concentration of 4500 to 18,100 ppmv had released from the Zyklon into the gas chambers, it would only be necessary to reduce that concentration by a factor of 100-500 times to reach this tolerable level.
It is not the case that the full concentration of Zyklon was present. At the largest Auschwitz crematoria (II and III), the Zyklon was removed after a lethal quantity of gas was given off, using the same devices which inserted it. At these buildings, where the large majority of gassings took place, essentially any absolute rate of outgassing could be achieved, at any temperature and humidity, by pouring in sufficient Zyklon. Once the victims were dead, the remaining carrier material could be lifted out by SS men wearing gas masks, to continue outgassing harmlessly into the open air until spent.
Inspection of Irmscher's paper shows (assuming the Erco carrier) that the concentration that would be present after 30 minutes, for example, would have been 20 to 40% of the total, i.e., 900-7200 ppmv. So it was only necessary to reduce the concentration in the gas chambers by a factor of 20-200 times in order for the Sonderkommando to enter even without gas masks. The remainder of the Zyklon could outgas safely in the outside atmosphere - without, needless to say, "poisoning the entire camp."
The gas chambers were 30 m long by 7 m wide: 210 sq m. They were 2.4 m high, for a volume of 504 cu m.  Those same chambers had a ventilation system with both intake and exhaust fans, capable of cycling 8000 cu m through the room each hour.  This is commonly referred to as 8000 ÷ 504 = 15.8 "air exchanges per hour."
Note that the Holocaust-denier Carlo Mattogno has misrepresented these figures in his essay, "Auschwitz: The End of a Legend." 
It is impossible, of course, to get an exact figure for how long it actually took to clear the air in the gas chamber. But we can obtain approximations through mathematical modeling. The equation used is a simple one: the concentration in the gas chamber is cut to 1/e, or about 37%, for each room replacement of air. Where C(t) is the concentration of HCN at time t in hours,
C(t) = C(0) (1/e)15.8t
This equation supposes that the fresh air mixes with the air in the chamber immediately and completely. In reality it does not do so. Ventilation systems are designed to have an air flow such that the expelled air has a higher concentration of poison, so this equation might seem conservative. In addition, the victims' corpses take up space which has not been figured into any of the below calculations; this would reduce the volume and increase the replacement rate, again indicating that this figure is conservative. But blockages caused by the same corpses, and the possibility of laminar airflow, might work in the other direction. All in all, this estimate will suffice.
Using this equation, if C(0) = 900 ppmv, the concentration is less than 20 ppmv after just 15 minutes.
The American Conference of Governmental Industrial Hygienists produces an Industrial Hygiene Calculator program for the Windows operating system.  When the size and ventilation rates of the gas chamber are converted to cubic feet and minutes, it returns identical results to the above equation.
It should also be pointed out that, halfway through their period of use, the size of these gas chambers was cut in half: 
Leichenkeller I proved in the end to be too large for a gas chamber. At the end of 1943, in order to "regularize" the operation of crematoria II and III, the camp administration divided their gas chambers in two, allowing no more than 100 sq m for the killing of 1,000 new arrivals (unfit for work) in 24 hours.
If one makes the logical assumption that the intake and exhaust vents were also blocked off in the unused portion of the gas chambers, this modification doubled the ventilation rate of the remaining portion. However, we will continue to use the figures from 1943; if a gassing from 1944 is referenced, ventilation times would be cut in half.
We return to the question of how long it would take to ventilate the gas chamber from the level used in killing to a level which the Sonderkommando could safely tolerate without a gas mask. We have seen that this took place in less than 15 minutes from an initial concentration of 900 ppmv.
If the initial concentration were more than seven times higher (7200 ppmv), owing to the nature of exponential math, the same concentration of under 20 ppmv would be reached in less than 23 minutes. Even if the residual Zyklon had not been removed and the chambers had the full concentration of 18,100 ppmv, the concentration would be less than 20 ppmv in 26 minutes.
In fact, since OSHA guidelines (above) give specifications not for maximum exposure but for mean exposure over fifteen minutes, we can use these values to understand what the Sonderkommando would experience. In the graph below, an initial concentration of 900 ppmv is assumed for the solid lines. The concentration is plotted in red. In blue is plotted the mean exposure over fifteen minutes for someone entering the gas chamber at the specified time. The dashed lines show the same information assuming an initial concentration of 7,200 ppmv: 
After ten minutes, in the former case, the ambient concentration was about 65 ppmv, and someone who entered the room at that point would receive a mean exposure to HCN, from t=10 minutes to t=25 minutes, of about 17 ppmv. Recall that 20 ppmv is the low end of Du Pont's symptom category: "slight symptoms after several hours."
It is thus safe to say that, with these assumptions, the Sonderkommando could enter the gas chamber ten minutes after ventilation began, wearing no gas masks, and experience no significant effects from the HCN.
If we instead assume the highest estimated initial concentration of 7,200 ppmv, the dashed lines would apply. Thus, the Sonderkommando could enter after eighteen minutes with no serious effects.
This conservative estimate fits with Pressac's conclusion that the doors were typically opened after twenty minutes of ventilation.[….][emphases ours]
Why an extraction system making it possible to safely enter the gas chambers within a maximum of twenty minutes after gassing would not be “powerful” enough for the purpose at hand remains the NT’s mystery.
NT: Even if the morgues had been converted for homicide later, as was argued by Pressac, it would have been simple to fabricate the ductwork necessary to heat and recirculate air through the Zyklon granules to ensure rapid release of HCN, adequate mixing, and then extraction.
We don’t know if it would have been “simple”, but let’s assume that it would have been. So what?
If the gas chambers already functioned adequately, why should they have bothered?
NT: But the story is painted into a corner with holes in roofs and wire-mesh introduction devices and OSS/CIA wartime aerial photos purporting to show the vent holes to introduce insecticide through the roofs.
Again, the Negationist team begs rather than proves the point that these Zyklon B introduction columns were simply invented rather than based on any conclusive and coincident documentary (an inventory list attached to a crematorium transfer deed) eyewitness (Kula, Erber and Tauber) and physical (air and ground photos) evidence. The convergence of these various sources of evidence, completely independent of each other, is explained in McCarthy/Van Alstine’s above-mentioned article, Zyklon Introduction Columns
, http://www.holocaust-history.org/auschw ... o-columns/
NT: Kremas IV and V, also at Birkenau, didn't even have that feature and purportedly used natural ventilation for their above-ground gaschambers.
As this is confirmed by several eyewitness depositions independent of each other, the “purportedly” is out of place.
NT: The technicians of death supposedly climbed ladders to toss in insecticide through the windows near the roof.
As it the “supposedly” in the above. The procedure described by witnesses may not have been as “elegant” from an engineering point of view as our opponents “would expect” the SS to have carried out an activity as demanding of technical finesse (see above) as mass murder. But it worked, and this was all the executors had to be and were concerned about.
NT: And while it is relatively easy to kill people, where is the "process engineering" for a scale of thousands of victims churned through this "River Rouge" of industrial annihilation like hot rolls?
Again, from whence do our humour-loving opponents derive the assumption that large-scale mass murder would require whatever they would be prepared to consider “process engineering”? Are we asked to believe that the killers would have endeavoured to find “elegant” technical solutions for mass killing, rather than being satisfied with a method that did the job, just because our opponents postulate that such concern with technical perfection would have been what “one would expect”?
As per their pattern, the Negationist team leaves this argument not with a conclusion based on the arguments that have been presented, but with a polemical assertion of the assumptions on which they rest.
Instead, the Allied blackbag intelligence operatives and their legal warriors in the warcrimes trials were not engineers and they left wide technical gaps in the liturgy. It is no wonder that for decades the technical problems in the Exterminationist story were not even addressed by mainstream historians.
All that needs to be pointed out here is that once again the Negationists are assuming the existence of the very Allied conspiracy they have yet to substantiate, explaining the evidence through the filter of this self-referential assumption. Once again, it is mere rhetoric in lieu of argument. The Negationist team does not see fit to specify these alleged "technical gaps" or "technical problems". All they have shown us is the gulf between what the evidence shows and what they personally think would have happened. This is the most plausible reason for the alleged "reluctance" of mainstream historians to address the nonexistent. They also clearly beg the question of whether there was ever any intention to create a "liturgy" rather than a conclusion based on evidence, that as such was dependent on and flexible to that evidence. If the Negationist team wishes to say that death probably took a bit longer than certain unspecified Sonderkommando witnesses thought, or that the SS could have produced a better gas chamber for use with Zyklon B, the Veritas team has no objection as these propositions have no effect whatsoever on our case. We never argued that the Sonderkommando were experts to a man in the medical properties of HCN, or that their testimonies were useful as the sole source of technical details on the technique and operation of gas chambers (indeed, we quite explicitly disavowed such a false methodology). But for the Negationist team to jump from there to the presumed existence of "Allied blackbag intelligence operatives" fabricating a "liturgy" is a leap of logic too vast for any reasonable person basing their conclusions on the evidence to make. There is no place for this sort of empty tripe in "scholarly debate".