How do we know the gas vans existed and were used to murder Jews in Chelmno and the East?
Holocaust deniers claim:
There are no primary Nazi documents proving that gas vans were built or used. If gas vans were used, we should expect Nazi documents about them. Thus, the existence and use of the gas vans is “hearsay” for which there is “little documentary evidence.”
For example, Holocaust denier Santiago Alvarez claims that the primary documents that deal with the construction and use of the gas vans are “ambiguous” and do not prove the gas vans ever existed.
The facts are:
Primary documents about the design and use of the gas vans survived the war. These Nazi documents prove that gas vans were designed and constructed in Berlin in late 1941 and early 1942; the vans were then sent to the Chelmno death camp and the Einsatzgruppen units in the occupied Soviet territories, to assist in the mass murder of Jews and others.
Facts about primary documents on the gas vans:
There is an entire file of Nazi documents related to the gas vans, but the most important are two letters concerned with the construction and use of the vehicles.
Letter dated May 16, 1942: Dr. August Becker to Walther Rauff, who was responsible for the construction and deployment of the gas vans.
Rauff, stationed in Berlin, sent Becker to inspect the use of the gas vans in the East and report back to him. The letter is his report. In the letter, Becker complained about:
The difficulties of operating gas vans in bad weather.
Becker notes that the larger vans could not be used all the time because if “it has rained for instance for half an hour . . . it simply skids away. It can only be used in absolutely dry weather.” The problem was that the “place of execution” was usually 10 to 15 kilometers off the regular roads, so that “in damp or wet weather it is not accessible at all.” (emphasis by author)
The difficulties of maintaining the gas vans under rough field conditions.
Becker notes that the “rough terrain and indescribable road and highway conditions” in the occupied Soviet territories were causing the caulking and rivets in the air-tight cargo compartment to loosen. As a result of the leaks, the men in the field were complaining of headaches. As a result, Becker noted that he had ordered that “during the gassing all the men were to be kept as far away from the vans as possible, so they should not suffer damage to their health by any escaping gasses.” (emphasis by author)
The lack of proper training and discipline by the drivers of the gas vans.
Becker reported that the men in the field were not following orders properly. “The application of gas usually is not undertaken correctly. In order to come to an end as fast as possible, the driver presses the accelerator to the fullest extent. By doing that the persons to be executed suffer death from suffocation and not death by dozing off as was planned. My directions now have proved that by correct adjustment of the levers death comes faster and the prisoners fall asleep peacefully. Distorted faces and excretions, such as could be seen before, are no longer noticed.” (emphasis by author)
Becker specifically says “places of execution,” “persons to be executed,” and “application of gas.” He notes that the German drivers’ health was being affected by leaks, and offers recommendations so that “death comes faster.” It cannot be clearer—the gas vans were used to murder human beings.
Letter dated June 5, 1942: marked “Top Secret,” from Willy Just, a German workshop foreman who adapted regular trucks into gas vans, to Walther Rauff.
The letter begins with the subject line: “Re: Technical adjustments to special vans at present in service and to those that are in production.” Just explains that “[s]ince December 1941 . . . 97,000 have been processed, using three vans . . .” However, based on “[p]revious experience” Just recommends several changes:
First, Just recommended that two slots should be added at the top of the rear wall of the cargo compartment to “facilitate the rapid distribution of CO [carbon monoxide].” (emphasis by author)
Second, Just suggested that the overall length of the cargo compartment of the larger vans should be shortened by three feet. Just noted that, on the minus side, this would decrease the number of “subjects” that could be “treated,” but on the plus side, this would mean that the space to be filled with carbon monoxide was smaller and the operation would take “considerably less time.” (emphasis by author)
Third, Just suggested that the lights in the cargo compartment needed to be covered with a steel grid to prevent damage from the “load.” It seems that when the “back door is closed and it gets dark inside, the load pushes hard against the door” where they can see the little light that remains around the edges. (emphasis by author)
Fourth, Just proposed that to help in the cleanup of vehicle after an operation, the new vans should have a watertight drain about 8 to 12 inches in diameter in the floor. The drain was to be equipped with a “sieve” so that “thin liquids” will drain out but “thicker dirt” will be collected so it can be quickly removed later.
Ingrid Weckert, a German Holocaust denier, claims that this letter does not prove “clearly and unequivocally” that the “load” was human beings. However, what load of goods—other than living human beings—“pushes hard against the doors” of the van seeking a last breath of non-poisonous air? What load of goods—other than living human beings—requires a drain to siphon off “thin liquids” but catches “thicker dirt” after each use? What load of goods—other than living human beings—requires that a light needed to be protected with a steel grid?
Holocaust deniers assert that primary documents about the gas vans are supposedly ambiguous. This is clearly false. Surviving Nazi documents show that they were designed and constructed in Berlin in late 1941 and early 1942. They were then sent to the Chelmno death camp and Einsatzgruppen units in the occupied Soviet territories, to assist in the mass murder of Jews and others.
By Jacques Lahitte (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
 Possibly a pseudonym.
 Santiago Alvarez and Pierre Marais, The Gas Vans: A Critical Investigation (Barnes Review, 2011), p. 273.
 You may read the text of the Becker/Rauff letter at http://www.holocaustresearchproject.org/einsatz/rauff.html.
 You may read the entire text of the Just/Rauff letter and see the scanned document at http://www.phdn.org/archives/einsatzgruppenarchives.com/documents/gaswagon5.html.
 Ingrid Weckert, “The Gas Vans: A Critical Assessment of the Evidence” (3.3.2 RSHA ‘Note’ of June 5, 1942) at http://vho.org/GB/Books/dth/fndwagon.html.