Zyklon B

from www.grin.com/document/150878

The commercial product Zyklon B
Properties, production, sale, handling

Scientific Study, 2008

Chapter 1 Introduction
In the following, an attempt is made to describe the commercial product Zyklon B as realistically as possible . The main basis for this is the scientific specialist literature from the years 1922 - 1945 . Additional information was obtained when inspecting the site and the still recognizable structural arrangements and buildings of the companies that produced the carrier material and the hydrocyanic acid for Zyklon B and the finished Zyklon B from it . The product was produced at that time in Germany in Dessau and in today's Czech Republic in Kolin and sold at home and abroad .
It is a pesticide whose active ingredient is hydrocyanic acid, a slightly boiling, water-clear, highly toxic liquid (boiling point 25.7°C) . Externally, Zyklon B looked like slightly reddish to yellowish moist semolina . It was packaged in the usual tin cans that are still common today for many foods . Gas masks were worn to open the cans and the finely powdered gritty or granular product containing prussic acid was poured out in a thin layer on prepared paper pads in well-closed rooms . The hydrocyanic acid evaporated almost completely in 1 to 2 hours and acted z . B. _in ships, mills, barracks, museums, homes, etc. as a gas against pests in the room, in clothes, beds, furniture, worm-eaten wood, valuable books, butterfly collections, etc .. Details of the commercial product were constantly being changed . The carrier consisted of one to three input materials similar to rock powder (mainly kieselguhr and/or gypsum) . At times the carrier was powdery, at times like grit, and at times it looked like very small dice . The liquid that was absorbed in the carrier had a complicated composition .Although it always consisted mainly of hydrocyanic acid, various impurities and additives that were contained or had to be added were changed so often between 1922 and 1945 that it is not clear what the commercial product was like at a certain point in time was put together in detail . There were cans of very different sizes. The content of cyanide, the component of hydrocyanic acid that acts as a poison, was indicated on the cans . Can sizes ranged from 50 g to 1200 g of cyanide . On average, the finished cans weighed about three times the declared cyanide content . The cans have also changed a lot over time .At times they were lined with rubber or provided with another protective coating . Later it was ordinary tin cans . The sheet metal thickness was at least twice as great as that of ordinary food cans, at least at the beginning . The filling date had to be stamped on the cans . They were only allowed to be used for one year . They had to pass strict strength and leak tightness tests by the Reichsanstalt für Materialprüfung in Berlin . For shipping, they had to be packed in solid wooden crates with spacers . Labeling of cans and crates was strictly prescribed by law .Only Zyklon B, in which the hydrocyanic acid was protected from dangerous decomposition and polymerisation reactions by suitable additives, was allowed to be shipped . There were no binding regulations on the content of odor warning substances . In addition, strict shipping documentation had to be adhered to .
The product designation was not always clear . It was usually referred to as "Zyklon B", but the word "Zyklon" also appears frequently, especially in advertisements from the distributor company Degesch (German Society for Pest Control) . The term "Zyklon process" was also common . In addition, for a while there was the product "Zyklon C", in which one component of the liquid active ingredient mixture, the so-called odor warning substance, was different and in higher doses .
Zyklon B was exported to many countries . There was another special form, mainly for export to the USA, especially for ship fumigation . The carrier used for this product was not a gritty fabric but soft cardboard discs that looked very much like round beer mats . These were soaked with the liquid made from hydrogen cyanide and additives and packed in tin cans like the gritty product . It was referred to as "Discoids" or "Zyklon-Discoids" .

Chapter 2 First there was Zyklon A
The Versailles Peace Treaty stipulated that no poison gas could be produced in Germany 1), 2), 3). This also included a product called “Zyklon” or “Zyklon A”, a liquid mixture of methyl cyanocarbonate and ethyl cyanocarbonate with about 10% methyl chlorocarbonate 4), 5), 6), 7). The product contained an average of 30% bound hydrogen cyanide 8). It was used as a liquid and sprayed indoors to control vermin . The importance of this product was small .
After the First World War, however, it was the starting point for the development of the much more important "Zyklon B" .
Chapter 3 From 1922 the new product was called Zyklon B
The new product Zyklon B was available from 1922 9), 10), 11). It differed fundamentally from Zyklon A. This was a liquid, Zyklon B a solid in which the liquid mixture of hydrocyanic acid, impurities and additives was absorbed .
Diatomaceous earth as a carrier
Based on experience from the explosives industry, finely ground kieselguhr was initially used as a solid, but very soon it was replaced by granular, gritty kieselguhr . The commercial product kieselguhr is usually a fine, light-colored to slightly colored powder that weighs between 280 and 500 grams per liter depending on the quality . There are also qualities that only approx . weigh 120 g/l . It is also offered in granulated form . It originates from Diluvian or Tertiary kieselguhr deposits that formed in water bodies when dead kieselguhr algae sank . There are deposits almost everywhere on earth .The largest and earliest mined in Germany is in the Lüneburg Heath (Unterlüß, Munster, Brehloh, Neuohe) . There hasn't been any mining there since around 1990 . Imported grades are shipped and distributed from Munster by United Minerals, USA . There are other, less important deposits in Germany in Klieken, (near Dessau) on the Vogelsberg, near Altenschürf, Stassfurt, Beuren and in Lusatia . In the Czech Republic there are significant deposits near Franzensbad, Bilin and especially at Forbes . The occurrences are similarly numerous in many countries .In the deposits, a distinction is made primarily between light gur, a light to white deposit with a silicic acid content of around 90%, and heavy gur, which only contains 70 - 80% silicic acid and also organic substances from the diatoms and therefore appears gray to green . In order to obtain commercial products, the light gur is dried, freed from impurities and usually sold as a fine flour product with a bulk density of less than 300 g/l . After drying, the heavy gur is often calcined, in the simplest case in kilns, similar to the kilns for charcoal production, otherwise in calcining ovens . It is obtained in pieces or in the form of flour . It is sold in these forms .The bulk density is significantly higher than that of light gur . Calcined it is approx . 450 g/l . If one examines kieselguhr microscopically, a wondrous world of geometric shapes and structures of countless different diatoms opens up, of which there are said to be more than 15,000 different ones . These forms are so characteristic of each occurrence that it is easy to microscopically assign a product to a deposit . Diatomaceous earth is used for a surprising number of different purposes , e.g. B. _ for silver polish and car polish .Important are the industrial applications as a raw material for chemical conversions, for glass and ceramics, for thermal insulation compounds in construction, for grinding and polishing agents, as a filler for rubber and plastic . Diatomaceous earth is particularly important as a filter aid for the filtration of beer, fruit juices, oil, etc. , for disinfection and decolorization and for special cleaning of liquids . The use of kieselguhr as a storage medium for dangerous liquids, e .g . B. _ of acetylene, of explosives and for Zyklon B of hydrocyanic acid . In the case of explosives, a well-known product is gurdynamite (kieselguhr with nitroglycerin) .Hard spirit (diatomaceous earth soaked with alcohol) used to be known in the household . Diatomaceous earth is also used as a gas cleaning agent and above all as a catalyst for chemical reactions . Details given here about kieselguhr were mainly found in a publication by F. taken from Kainer 12). In addition, information about diatomaceous earth from manuals was used 13), 14), 15), 16).
Complicated hydrocyanic acid mixture of active ingredients
If you put blotting paper in one spot of an inkblot, it will soak up all the ink . Soaking the Zyklon B carrier with the active ingredient mixture of hydrocyanic acid also works in the same way . It was a complicated mix for various reasons . For Zyklon B, the hydrocyanic acid in Dessau and Kolin (Bohemia) was produced from sugar production residues by heating in two stages to approx . 800° C, then to approx . produced at 1600°C . Some impurities in the hydrocyanic acid originate from this process, above all benzonitrile, acetonitrile and naphthalene 17). In addition, there are still residual amounts of water .
The impurities are likely to have made up a total of about 3%, of which acetonitrile and benzonitrile each accounted for about 1% .
Because hydrogen cyanide tends to decompose dangerously even in a weakly alkaline environment, acidic or acidic ingredients must be added to the liquid mixture of active ingredients . When using hydrocyanic acid, including Zyklon B, there is a risk of poisoning because the hydrocyanic acid smells so weak that the danger is not noticed or is noticed too late . For this reason, a so-called warning substance is added to the mixture of hydrocyanic acid and active ingredients; one could say: a tear gas . The first Zyklon B products were based on the predecessor product Zyklon A in these two points .The odor warning substance contained there, chlorocarbonic acid methyl ester, combines both properties in one additive: It is a strong odor warning substance and at the same time acts as an acidic component, i . h . as a stabilizer for hydrocyanic acid . Zyklon B probably contained 3-5% of this additive . It was soon noticed, however, that various disadvantages were associated with this . For this reason, stabilizers and odor warning agents were used as two different products in the years that followed and changed again and again .
This is reported in Chapter 6 .
100 g of the first Zyklon B probably contained the following proportions of the various substances: kieselguhr approx . 50 g, hydrocyanic acid approx . 46.8 g, methyl chloroformate approx . 2 g, sulfuric acid 0.20 g, impurities approx . 1 g .
Chapter 4 Modern pest control with Zyklon B
Hydrocyanic acid has been used to combat harmful insects for around 120 years . Hydrocyanic acid was used for the first time in 1877 to combat pests in insect collections 18). In 1887, fumigation of citrus trees to control scale insects and other pests was introduced in California 19).
Illustration not included in this extract
fig . 1 Tree fumigation in Egypt List of sources 20)
From there, the procedure spread worldwide to countries such as Spain, Italy, Egypt, Syria, Palestine . In southern Italy alone, 5 million trees were planted between 1928 and 1931 at a cost of around . RM 0.5 per tree fumigated .
Similar fumigation figures apply to Spain, Egypt, Palestine, Syria . The process was also used in countries in Africa, South America, even Japan . According to estimates, around 25 million were sold in the 1930s . Trees fumigated, including at least 7 million in California and at least 8 million in Spain . trees per year . 21), 22) . Before the introduction of Zyklon B, around 25 million . kg of sodium cyanide consumed .
In Germany, the use of hydrocyanic acid for pest control began with the gassing of a mill belonging to the Adam Schulz councilor of commerce in Heidingsfeld near Würzburg in 1917 23), 24).
The aim was to combat the flour moth . There were no tree fumigations in Germany . On the other hand, gassing through the mill with hydrogen cyanide has prevailed . By 1929, 12.5 million . cubic meters of mill space gassed 25).
In Germany, hospitals, barracks, ships and many other buildings were soon gassed with hydrogen cyanide .
From the beginning of hydrogen cyanide fumigation until around 1925, the so-called vat process was used . To do this, place the calculated amount of sodium cyanide in a vat and dilute the required amount of sulfuric acid with water, whereby the diluted sulfuric acid becomes warm . Then you add the diluted sulfuric acid to the sodium cyanide under respiratory protection or with a remote control; as a result, large amounts of hydrocyanic acid develop with effervescence . A variant of this process are "hydrocyanic acid generators", mobile devices that can produce hydrocyanic acid as needed from sodium cyanide and sulfuric acid 26) .Instead of producing hydrocyanic acid on site using a chemical reaction, liquid hydrocyanic acid was also used, which was conveyed into the fumigation room from small storage containers with pumps and hose lines . For example, tree fumigations were carried out in California and Spain 27).
Another fumigation method used calcium cyanide, a light-colored, fine powder that releases hydrocyanic acid, especially when moisture is present . Therefore, this product and process has been used almost exclusively in greenhouses . The procedure was a . Called the “cyano gas process” 28), 29).
The hydrocyanic acid product Zyklon B was very successful from the moment it was introduced . This was because, from the start, it was more convenient, cheaper, and safer to use Zyklon B rather than messing around with the vat method or liquid hydrocyanic acid . The main disadvantage of the vat method was that one had to handle sodium cyanide, concentrated sulfuric acid and water, and that about 10% of the cyanide remained in the preparation vat and had to be disposed of .The main disadvantage of using liquid hydrocyanic acid was the extreme risk of poisoning in the event of incorrect operation and the safety risk of liquid hydrocyanic acid, which the manufacturer had to responsibly protect against decomposition and explosion with stabilizer additives, and which had to be particularly pure because of this risk .
In contrast, the modern product Zyklon B represented a huge step forward:
The hydrocyanic acid was bound to an inert carrier, the evaporation was slowed down, the risk of explosion eliminated, it only had to be protected against slow decomposition in kieselguhr by stabilizers .
In use, dosing was not a problem as there were many different sized doses . This made fumigation easier and correspondingly cheaper .
Chapter 5 The market for Zyklon B is expanding
Hydrocyanic acid fumigation using the vat method or with liquid hydrocyanic acid were "old market products" . Zyklon B was the modern improved "market product" . However, Zyklon B practically did not go into large existing markets for hydrogen cyanide fumigation, the fumigation of citrus orchards . On the other hand, new markets opened up in mills against flour moths, in warehouses and cold stores with mixed stocks of food against mice, rats and ants, in cocoa factories against the cocoa moth, in food and beverage factories against dried fruit moths and other pests, in tobacco sheds against the tobacco worm , in hide and gut stores against the bacon beetle; in ships against rats; in barracks, barracks, apartments, railway carriages, airplanes, etc.against bugs, fleas, lice, fur and clothes moths and other pests; in churches against wood tick and wood pests and in many special applications such as libraries, museums etc ..
As early as 1926, four years after the introduction of Zyklon B, 250 t of hydrocyanic acid had been used in the cyclone process . 30)
A requirement of 10 g hydrogen cyanide per cubic meter, corresponding to 10 t per million cubic meters, is usually used to convert the volume of gassing with hydrogen cyanide .
For 1926, one can see from a graph that in the port of Rotterdam alone there was 1.7 million m³ of shipping space, corresponding to approx . 17 t hydrocyanic acid was gassed with Zyklon B. 31)
“The spaces between the transverse lines each mean 100,000 cbm . The entered digits represent the number of gassed cubic meters . "
Illustration not included in this extract
fig . 2 ship gassings in the port of Rotterdam List of sources 31)
Zyklon B was no longer manufactured after 1945 . In the former GDR, a successor product called "Cyanol" was manufactured from 1951 to 1968 with discs of soft cardboard as the carrier material . There was no longer a gritty product there .
For 1927, a similar graphic for fumigations in Germany gives a total volume of 9 million . m³ per year, corresponding to approx . 90 t hydrogen cyanide from Zyklon B to 32), 33).
Illustration not included in this extract
fig . 3 total gassings in source index 32), 33) Germany
By 1932 around 100 million were sold in Germany . cubic meters of space – corresponding to 1000 t of hydrocyanic acid – gassed with Zyklon B, including 16 million . Cubic meters in 1300 mills 34)
By 1937 it was 132 million . Cubic meters of fumigated room, of which 22 million . cubic meters of mills and 80 million . Cubic meters of shipping space, corresponding to approx . 1320 tons of hydrogen cyanide . 35)
At that point in time, several thousand tons of hydrocyanic acid per year were used for pest control worldwide using various fumigation methods . 36)
The cyclone process is particularly suitable for large-scale fumigation . The largest mill was 156 000 m³, the largest building 242 000 cubic meters and the largest ship 160 000 cubic meters 37).
There is no information in the specialist literature about the consumption of Zyklon B in Germany after 1937 . The consumption of Zyklon B in Germany between 1922 and 1926 was 50 - 70 t/year; between 1926 and 1932 at 100 – 130 t/year and between 1932 and 1937 at 60 – 90 t/year . At the end of the war, the production capacity and total sales of the factory that, according to the generally accepted view, produced the main quantity, Dessauer Zuckerraffinerie GmbH, Dessau, were between 10 and 20 t per month 38), 39), corresponding to 120 to 240 t/year . In the years 1939 - 1944 most of these quantities were used for civil and military purposes in the German sphere of influence .Two important reasons for the rapid spread and market success of Zyklon B should be mentioned in particular: the rapid increase in large-scale fumigation and the construction of countless technically particularly efficient, stationary gas chambers . Large-scale fumigations on objects in Cologne, Mainz, Krefeld, Solingen, Frankfurt, Wiesbaden, Ludwigshafen/Rhine and on foreign objects and ships are reported in detail as early as 1927 with illustrations of the objects 40). The gassing of the largest German ocean liner, the "BREMEN" of North German Lloyd, was reported in 1935 41). The strong increase in ship fumigation worldwide was essential for the market success of Zyklon B in export .This was due to the fact that in June 1926 an international sanitation agreement to combat epidemics, especially typhus and smallpox, was signed by over 100 countries . Article 27 refers to combating rats as carriers of such diseases on ships .
The Hygiene Commission of the League of Nations and the Office International d'Hygiene Publique have joined the agreement 42). It was introduced in Germany by a law on the international medical agreement dated 18 03 . enacted in 1930 43). Increasing amounts of Zyklon B have been used for ship derathing in many seaports .
There are particularly extensive and detailed reports on the deratting of ships in US ports using various hydrogen cyanide fumigation methods . These reports also contain detailed comparisons of the use of Zyklon B and Zyklon Diskoids and comparisons of these two products with the use of liquid hydrocyanic acid 44) – 51).
Another reason for the market success of Zyklon B was the numerous stationary gas chambers with a simple, safe and effective technology for gassing and ventilation, which were set up in many German cities, the first before 1928 in Essen, Hamburg, Dresden, Breslau, Berlin and Flensburg . The first detailed descriptions of such gas chambers date from 1929 and 1930 52) - 57).
The costs in RM for the disinfestation of individual items amounted to e.g. B. _ in Koenigsberg 4.50; Mainz: piano 4.60; wardrobe 7.20 / 8.00; Quilt 0.55/0.40 . From around 1936, technically greatly improved circulatory gas chambers were built with safe charging from outside and the possibility of switching from circulatory to ventilation by changing the position of a four-way valve 58) 59). It was even thought of building large-capacity gas chambers on the outskirts of the big cities on the grounds of gas stations, in which whole truckloads, especially when moving furniture vans with removal goods, were to be devestated 60). Stationary gas chambers were so widespread that in 1940 the clothing of 5 million. members of the Wehrmacht and prisoners were poisoned with hydrocyanic acid 61). The stationary gas chambers and the disinfestation process were technically so advanced that a complete cycle of loading, gassing, ventilation and emptying could be carried out in a circulation chamber in 75 – 90 minutes, although a hydrocyanic acid gas intensity of 10 g hrs/m³ is required . In a chamber with a volume of 10 m³, 150 – 200 outfits could be devestated per day 61). In Germany, stationary gas chambers had to be licensed individually . Mobile chambers were forbidden except for the purpose of decontamination of shipments of plants 62).
Mobile gas chambers for disinfesting furniture also existed abroad . A gas-tight furniture van with a capacity of 20 m³ was stationed in Odense, Denmark 63), 64), 65).
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fig . 4 Mobile gas chamber furniture truck, bibliography 65) Odense, Denmark
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“Of course, this gas-tight furniture van does not have to be driven into a gas chamber: this method is simpler and cheaper . In Denmark it was introduced shortly after the war; in England it is very common . "
fig . 5 Mobile gas chamber furniture truck, Odense, Denmark List of sources 64)
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fig . 6 Mobile gas chamber furniture truck, Odense, Denmark List of sources 63)
Mobile gas chambers were used on a larger scale with the support of the government in England 66), 67), 68) .
Illustration not included in this extract
"Housing hygiene in England . Disinfestation of removal goods in mobile chambers"
fig . 7 Mobile gas chamber furniture truck England List of sources 66)
At the end of the section on the market successes of Zyklon B, a spectacular gassing of the parish church in Kefermarkt - north of Linz - with hydrogen cyanide to combat the winged altar infested with wood pests should be mentioned 69). In the 6000 m³ large church room on 04 . 11 . 1929 75 kg Zyklon B used, on 08 . 11 . 14.4 kg were refilled, on 12 . 11 . the fumigation was terminated . The successful fumigation is particularly interesting because all details are documented in detail .
Chapter 6 The Zyklon B concept Carrier, hydrocyanic acid mixture, tin cans and overall packaging
For transport and use, liquid hydrogen cyanide must be as water-free as possible, stabilized by chemical additives and filled in heavy, pressure-resistant steel bottles .
The Zyklon-B concept has decisive advantages against this: absorbed in the carrier material, the unpleasant properties of hydrocyanic acid are greatly reduced . Due to slow evaporation from the carrier, the high toxic effect develops more slowly, the risk of explosion is practically eliminated by the dilution in the carrier, and the packaging can consist of simple tin cans .
This concept has remained the same since 1922 . In a patent of DESCH from 20 . 06 . In 1922 it was patented 70). The details were continuously improved between 1922 and 1945 and frequently changed and adapted to the circumstances . The following sections report on this .
Chapter 6 a The carrier
Diatomaceous earth was the carrier used in the early years . Some information about this is in Chapter 3 . Further details are recorded here .
The first practical test of a commercial product Zyklon B is reported in 1924 . 71) After extensive shaking, impact, dropping and impact tests with individual cans and complete packaging of Zyklon B, the Reichsanstalt für Materialprüfung Berlin came to the conclusion that the contents of the cans are defective because the carrier material has compacted into a cement-like mass and liquid prussic acid has escaped and that the overall packaging is defective because the cans in the overall packaging have rubbed against each other and have become leaky as a result . The Reichsanstalt therefore recommends securing the cans against each other with cardboard lids and finding a less "fragile" carrier material .This report shows that at that time the carrier was finely ground diatomaceous earth or very easily disintegrating kieselguhr granules . In 1932, Diagries reported that 1 part by weight of hydrocyanic acid was absorbed in 1.3 parts by weight of Diagries 72). A year earlier, a mixture of Diagries/hydrocyanic acid in a ratio of 1.3/1 had been investigated in tests on the explosive properties of hydrocyanic acid 73). It is possible to derive something from this information for the carrier material in Zyklon B: The lighter the kieselguhr is, the more it absorbs, the heavier it is, the less . Today's products from United Minerals, 29633 Munster, confirm this clearly .Grade FN 1, bulk density 170 g/l absorbs 145 g of water per 100 g Gur, grade FP 3, bulk density 190 g/l absorbs 140 g per 100 g Gur, grade 14/1K, bulk density 470 g/l absorbs 70 g per 100 g Gur and type G 1000, bulk density 530 g/l absorbs 65 g water per 100 g Gur . This is due to the fact that the skeletons of the diatoms are largely preserved in the light products and the existing cavities are therefore larger . However, since very light products are difficult to handle, they are processed into granular products with grain sizes between the size of a semolina and a pea if possible . This partially destroys the cavity structure of the diatoms, which leads to a higher bulk density and lower absorbency .The diagries mentioned above is possibly a product that has been made granular by calcination (heating to 700-800°C) and has a bulk density of ca. 450 g/l had . Presumably such a carrier was used as a carrier for Zyklon B for a while . There was probably also a time when Zyklon B came on the market with different carriers, because from 1926 there are also reports of Zyklon B in which 1 part by weight of hydrocyanic acid was absorbed in 1 part by weight of carrier 74), 75). Diatomaceous earth, also called "diatomite", was reported as a carrier until 1932 . The product is described as "fine brown sand" 76) , "coarse powdery reddish-brown mass"77) , “granular diatomaceous earth” 78) , “porous granulated earthy substance” 79) , “diagries” 80) , “kieselguhr earth” 81) or “granular diatomite” 82) . In many more writings, the carrier is referred to simply as kieselguhr, diatomite, or earthy substance .
The term "lambda cube" for a new carrier substance appears for the first time in 1929 83). Presumably this is a carrier material that consists predominantly of gypsum . In 1931, the carrier was referred to as a “kieselguhr-like mixture”, “Erco” 84). In 1933 a comprehensive publication was published in book form by the responsible DESCH technician, Dr. G . Peters, with a picture of Zyklon cans of different sizes and with the pictured carrier materials "Erco", "Diagries" and "Discoids" 85).
Illustration not included in this extract
fig . 8 Fig . 9 "Erco" "Diagrieß" "Discoids" Zyklon cans different Zyklon cans with different carrier contents (left and right poured materials . carrier material) List of sources 85) List of sources 86)
From that point onwards, the carrier(s) of Zyklon B are practically not mentioned, except in an almost identical figure 86).
Illustration not included in this extract
fig . 10 Bibliography 89) Fig . 11 List of sources 89)
Company brochures from Rheinhold & Co contain some product information in addition to material figures and extensive technical tables on heat, cold and sound insulation . In the years 1928 and 1931 these writings were called "WSW-Kalender" . 87) In the 1928 paper, p . 24 – 28 are the product designations “kieselgur light mass T 108”, “Lambda” material and “Dia” material” . As an appendix to S. 24 are shown in enlarged representations of "Kieselguhr" from the Klieken plant (near Coswig) and "Lambda-Material DRP" 89).
On the cover of the publications from 1928 and 1931 there are stylized signs for thermal insulation, the company Rheinhold & Co and the Greek letter Lambda 90).
Illustration not included in this extract
fig . 11 Writing Rheinhold & Co 1931 cover page list of sources 90)
The writings of the years 1933, 1935, 1937 and 1940 are called "WSW-Tabellarium" 88) . All of these company publications contain the names and addresses of the parent company, the sales offices and the factories with pits . The outer cover of typefaces 1933–40 is simpler, containing only the stylized symbols of the company name and the lambda material 91).
Illustration not included in this extract
fig . 12 Writing Rheinhold & Co Sources 91) 1940 cover
Among other things, the product designations "Kieselgur-Warmschutzmasse" and "Dia-Gries" are in the writing from 1933; in the 1935 "Leichtdia", "Dia", "Kieselgur-Leight Mass T 108" and "Dia-Gries"; in the 1937 "Leichtdia", "Dia", "Leichtgips KWF", "kieselguhr-light mass T 108" and "kieselgur-Wärmeschutzmasse"; in the 1940 "Leichtdia", "Superdia", "Dia-Gries", "Leichtmasse T 108" and "Kieselgur-Wärmeschutzmasse" .
The products "Lambda" and "Dia" used at times as a carrier for Zyklon B can be clearly identified in the company documents of Rheinhold & Co. The carrier material for Zyklon B with the designation "Erco" is not mentioned in these documents .
It was not until 1945 that statements on the carrier substance of Zyklon B were found again in FIAT and BIOS reports . At one point it says: "Cyclon is the trade name for hydrogen-cyanide absorbed on kieselguhr, kaolin, erco (gypsum) or similar absorbents" 92). Elsewhere: "Cyclon B is manufactured by the Dessauer Zuckerfabrik, who obtain the active agent HCN from the sugar beet residues . The 79% HCN is poured on CaSO4 starch lumps” 92) and at another point: “Cyclon B consists of liquid HCN, of high purity, with a little bromoacectic ethyl ester as a lacrimator and oxalic acid as a stabilzer, sorbed on thick paper discs, silica gel, gypsum or a similar material” 93).
Table 1 represents an attempt to reconstruct the composition of the carrier substance for Zyklon B from the information in the scientific specialist literature at different times .
Table 1 Carrier material for Zyklon B 1922 – 1945. (Reconstruction)
Information on the carrier for Zyklon B
Illustration not included in this extract
The information available in the specialist literature says nothing about the composition of the carrier used from around 1931 onwards . However, considerations and experiments make it possible to reconstruct the composition to a large extent:
Pure gypsum with water gives gravy- or mush-like preparations that cannot be made granular before setting . To do this, they have to be broken up and sieved after they have hardened . Bulk densities of 900 to 1000 g/l are achieved, under the conditions of the production of light gypsum also significantly lower bulk densities . Set and dried plaster absorbs about 30 g of water per 100 g, light plaster more . If you put plaster with previously prepared water-starch gel, then these absorption values are a little cheaper but still far from satisfactory .Pure diatomaceous earth has the disadvantages described above for the carrier material for Zyklon B from the years 1922-25, so it is not suitable for a good carrier material either . Preparations made from diatomaceous earth alone do not harden like plaster of paris . Mixtures of kieselguhr with water do not produce a sauce-like or porridge-like preparation, but rather brittle and crumbly preparations . Even from these considerations of the pure ingredients gypsum and kieselguhr, it is clear that mixtures based on a suitable recipe could possibly lead to a certain optimum of the properties required for a carrier . The experiments described below show this .
If you mix dry premixes of different composition from kieselguhr and gypsum with water on the one hand and with a previously prepared water/starch cone mixture on the other hand, you will find that water/starch cone is cheaper because kneading is easier and gentler than with water alone . A water/starch cone made by briefly heating 100g of water with 6g of starch works well for this . If one compares potato starch with corn starch, one finds that better experimental carrier materials are obtained with starch gel made from corn starch than with potato starch . (Lower bulk density, better absorbency) .It can therefore be assumed that corn starch was used to produce the carrier for Zyklon B.
Systematic testing, as summarized in Table 2, resulted in a formulation that is believed to be very close to the formulation used to make a carrier for Zyklon B between about 1931 and 1945 . The following products were used for the experiments described here: plaster: model plaster, company Hilliges Gipswerk, 37250 Osterode; Diatomaceous earth: type FP 3 (product from the USA), United Minerals, 29633 Munster; Corn starch: Maizena product, Maizena company, 74074 Heilbronn . Starch gel was prepared from 100 g water and 6 g starch by briefly heating . Gypsum and diatomaceous earth were dry premixed in different proportions .The gypsum/kieselguhr premixes are homogeneously mixed with the cooled starch gel . This mixing is a process like kneading a dough . After this kneading, the finely crumbly moist product is sieved through a granulating sieve with a mesh size of 1.1 mm . The yields of acceptable particles given in the table below are the amounts of sieved product weighed out after drying .
Table 2 Composition and properties of test products from corn starch gel and gypsum/kieselguhr premixes.
Illustration not included in this extract
Mixing, granulating, drying, then determining the properties
Table 2 - continued properties
Illustration not included in this extract
1) Based on the dry solids used, gypsum, kieselguhr, corn starch + crystal water of the gypsum after setting .
The properties of the test mixtures no . 3, 4 and 5 largely correspond to those described for the carrier material for Zyklon B from the period 1931 - 45: production via granulating sieves, high yields of good grain, a sand-like product, grain size 0.1 - 0.9 mm, bulk density approx . 330 g/l, water absorption (also applies to a large extent to hydrogen cyanide absorption) more than 100 g/100 g, composition of gypsum, kieselguhr and starch .Slightly simplified, this carrier consists of almost 45% gypsum, approx. 50% kieselguhr and 5% corn starch, whereby in 1931 - 45 instead of kieselguhr FP 3 from United Minerals, a corresponding kieselguhr from the Klieken deposit (between Coswig and Dessau) probably kieselguhr K 150 or from a deposit near Munster (Lüneburg Heath) and instead of the gypsum from Osterode used, a similar gypsum from the Rottleberode plant in the Harz Mountains was probably used . Experimental mixture 4 is probably the closest to the carrier used in 1931-45.
In a 1942 article in the Journal of Hygienic Zoology, R. Irmscher, director of the DESCH company, who was named as an interviewee in a FIAT report: "In one case, cardboard discs were used as the absorbent material, in the other case Erco cubes (highly porous gypsum material), i.e. the two most common carrier materials in practice for hydrogen cyanide gas penetration" 94) . This also supports the assumption that it was a gypsum/kieselguhr mixture whose exact composition was not specified in order to secure and preserve competitive advantages and know-how .
A carrier material made of gypsum/kieselguhr was obvious at the time, because heat protection masses and heat insulation articles were made from such materials on a large scale, the material of which was also suitable for absorbing liquids . There were many patents dealing with the manufacture of lightweight gypsum plaster for thermal insulation, soundproofing and liquid adsorption . Patents from France, the USA and Canada primarily dealt with the production of soundproofing materials from gypsum and gypsum mixtures with foaming agents 95), 96), 97). The company Reinhold & Co United Kieselguhr- und Korkstein-Gesellschaft, Berlin SW 61, Belle Alliance Platz 13, (Reinhold & Co), with the delivery works Hansa Werk AG Abt .Coswig-Anhalt, Coswig-Anhalt; Cork block factory C. & E . Mahla GmbH, Nuremberg/Lauf; Korksteinwerk GmbH Brand-Erbisdorf/Sa and Suberit-Fabrik AG, Mannheim-Rheinau owned the patents DRP no . 499316 and no . 354426 98), 99). The first patent concerned the manufacture of thermal insulation compounds . Insulating pipes and insulating pipe half-shells and malleable insulating compounds were made from this, especially for heating lines, which were wrapped with textile tape after attachment . In the 1920s, the trade names for these items from Reinhold & Co were “Lambda material”, “Lambda items”, etc.The material probably consisted mainly of gypsum and additions of slaked lime and water glass . Asbestos fibers were added to the manufacture of finished articles, or pig's bristles in the case of thermal insulation masses to be applied directly . First, the materials were mixed to a creamy paste, then the shaping or shaping took place . wrapping with textile tape . After drying, salable products were obtained .
Later, in the 1930s, the trade and product designations for these items from Rheinhold & Co were called “Dia-Material”, “Dia-Articles” such as . B. _ "Light slide 300", "Slide 350", "Slide grit coarse", "Burned slide material" .
In the late 1930s and 1940s, the largely optimized carrier materials for Zyklon B made from gypsum/diatomaceous earth/corn starch were called “Erco” . According to the author's knowledge, these products were manufactured by the company Reinhold & Co, Lieferwerk Coswig-Anhalt and delivered to the sugar factory in Dessau .
Reinhold & Co's second patent was for gypsum adsorbents . It claimed the use of porous plaster to absorb liquids . The admixture of kieselguhr is always included, but not expressly mentioned .
There was a completely different kind of carrier, the "discoids", "discs", "Zyklon-discoids" or "HCN-discs" . These were round discs made of soft cellulose fibers, perforated on the inside, very similar to the well-known beer mats . These discs were also soaked in hydrocyanic acid and packed in tin cans . Zyklon discoids were manufactured for export, primarily to the United States . They were mainly used for ship fumigation . Therefore, the standard cans contained 454 g (1 pound) and 1134 g (2.5 pounds) . The first shipments of Zyklon discoids (probably 1930-1931) to the US contained thicker discs made from soft paper fibers (like beer coasters).. Subsequent shipments (from about mid-1931) contained thinner discs made from specially manufactured softwood fibers . They could absorb around 2.5 times their own weight in liquid hydrogen cyanide . Zyklon B and Zyklon discoids were extensively tested in the New York harbor “quarantine station” . These tests show that there is practically no difference between Zyklon B and Zyklon discoids in terms of application, with one exception: the evaporation of hydrogen cyanide from Zyklon discoids is somewhat slower than from Zyklon B . Above all, the odor warning substance (at that time 5% chloropicrin) is retained longer than in Zyklon B.Overall, however, the two products are said to be practically the same . The details given here are taken from publications of the American Public Health Service 100), 101) . The advantage of the Zyklon discoids is that small amounts of hydrocyanic acid can be dosed very precisely with the individual discoids, which is important for ship fumigation for small individual rooms . The disadvantage is that the can lids have to be opened very cleanly all around, otherwise the discoids will not fall out easily . After 1931 discoids are used, except in the publication by G . Peters 102) practically no longer mentioned .Therefore, it is likely that the product has not changed further since then .
Chapter 6 b The hydrocyanic acid active substance mixture
In chapter 3 it was mentioned that the hydrocyanic acid-active substance mixture of hydrocyanic acid, impurities, odor warning substance and stabilizers was complicated and composed differently at different times . Details are reported in this chapter . Above all, the frequent changes in the odor warning substances and the hydrocyanic acid stabilizers are recorded here . On the other hand, for the secondary components or impurities in the hydrocyanic acid itself, which are production-related, it is assumed that the secondary components reported in 1930 apply to the entire period 1922-1945 . Specified are 1% benzonitrile, 1% acetonitrile, naphthalene 17) .Since there were probably improvements in production as well, it is assumed that the average for the years 1922-45 was 0.5% benzonitrile, 0.5% acetonitrile, 0.1% naphthalene, 0.5% water and 0.4% other ingredients; So a total of 2% impurities were contained in the hydrocyanic acid . This should largely correspond to reality .
The odor warning substance was intended to irritate the nose and eyes like tear gas, thereby drawing attention to the highly toxic, bad-smelling hydrogen cyanide and preventing people from entering rooms under hydrogen cyanide gas . The principle is the same as adding foul-smelling substances to town gas . The stabilizer - another additive - should neutralize alkali reserves in the carrier and in the hydrocyanic acid itself and thus protect the hydrocyanic acid from self-decomposition .When hydrogen cyanide was sucked up, there was no danger of an explosion due to self-decomposition, as is the case with liquid hydrocyanic acid, but if the carrier material and/or hydrocyanic acid were insufficiently stabilized, hydrogen cyanide that was sucked up also self-decomposed, which showed up as a brown to black discoloration .
As explained in Chapter 3, 100 g of the first mixture of hydrocyanic acid substances probably consisted of about 93.6 g hydrocyanic acid, 4 g methyl chloroformate, 2 g impurities and 0.4 g sulfuric acid . Methyl chloroformate acted both as an odor warning agent and as a stabilizer; Sulfuric acid was also used as a stabilizer .
From the beginning of the Zyklon B product, there were numerous patents on hydrocyanic acid stabilizers . Patented z . B. _ the acid treatment of substrates 103) , acid-releasing substances 104), 105) , organic acids 106) , 107), 108) . Oxalic acid is of particular importance because it stabilizes hydrogen cyanide even in very small quantities 109) . Most of these patents are from Degussa, Frankfurt .
In the early days of Zyklon B there were also several patents on odor warning substances . There were patents on odor warning substances that could split off acid and were thus stabilizers at the same time 110) , on cyanogen bromide, cyanogen chloride as “pre-warners” and chloropicrin, bromoacetophenone as “post-warners”; via methyl bromoacetate, etc. 111) , chloropicrin 112) , chlorocyan 113) and bromoacetophenone as early and late warnings 114) .
The number of these patents alone shows that there is no simple, unambiguous solution for stabilizers and odor warning substances for hydrogen cyanide . This is also one of the reasons why Zyklon B was particularly frequently changed in these two additions .
Legally, there was a major difference between the stabilizer for hydrocyanic acid and the odor warning substance: A stabilizer for Zyklon B was mandatory: "The hydrocyanic acid must be supplemented with an additive recognized by the Chemical-Technical Reich Institute for type and quantity, which can also be a warning substance. be made permanent . " 115)
In 1941, the SS received an exceptional permit 116) , which, however, only referred to the part of the applicable Reich regulations and implementing regulations that governed their application .
On the other hand, an odor warning substance was not mandatorily required by any applicable regulations 117) . In the USA, however, there have been efforts for some time to legally prescribe the addition of an odor warning substance to hydrocyanic acid . 118)
The chemical stabilization of the hydrocyanic acid begins with the carrier and continues in the mixture of active ingredients in the hydrocyanic acid: There are types of kieselguhr that have a higher and other types that have a lower content of calcium oxide and magnesium oxide, i.e. a higher or lower alkalinity . You have to choose varieties that contain as few of these components as possible, or you have to reduce the levels of these substances by post-treating the kieselguhr (annealing, washing with acid) before you can use it as a carrier for hydrogen cyanide . Gypsum is more favorable in the direction because it possesses practically no alkalinity .
In the early days, only diatomaceous earth was used as a carrier (see above) . According to a report by the Chemical-Technical Reich Institute 119) , the kieselguhr used at the time, if it was not stabilized, led to the decomposition of the hydrocyanic acid in the Zyklon B. There are no written reports on the type selection of the kieselguhr used and the exact way in which the kieselguhr was pre-stabilized and pre-treated . However, one can assume that a kieselguhr that was as low in alkali as possible and probably ignited was used in the period from 1922 to around 1929, because only around 77 g of hydrogen cyanide per 100 g of carrier material are mentioned as absorbing capacity, which indicates a higher bulk density .The hydrocyanic acid was probably stabilized by the addition of about 0.1% sulfuric acid and contained the additional stabilizing odor warning agent chlorocarbonic acid methyl ester . After 1929 there is hardly any information about the type and quantity of the stabilizer . Up until around 1930, methyl chlorocarbonate was mentioned as a stabilizer/odor warning agent 121) . Add 0.1% sulfuric acid for additional stabilization . From about 1929/30, a new carrier material appeared that was less alkaline as such due to the gypsum content . Therefore, other stabilizers could be used .The sparse evidence available points to 0.2% oxalic acid in the hydrocyanic acid 119) , 120) in combination with a new odor warning substance chloropicrin, which does not have a stabilizing effect . (See below) . Even if there is no explicit reference to this in the available documents, it is obvious that so much sulfuric acid was added to the mixing water or gel for the gypsum-kieselguhr mixture that this corresponds to 0.1% of the hydrocyanic acid to be adsorbed, i.e. to 100 ml of water approx . 0.05 g of sulfuric acid . Such a combined stabilization is so safe that hydrogen cyanide decomposition is impossible, which is proven by practical experience up to 1945 .
Up to around 1929/30 approx . 3% methyl chlorocarbonate used 121) , 122) . There were also variations within this period . A combination of 2% chloroformic acid methyl ester and 2% bromoacetic acid ethyl ester is also reported 123) . In the annual report of the Chemical-Technical Reichsanstalt from 1930, there is a report on cyanogen chloride as an odor warning substance 17) . After the further releases, the product was soon dropped again . A "Zyklon C" with 10% chloropicrin also appears to have been a test product 124) .
In 1929, the carrier material was switched to gypsum and then to gypsum / kieselguhr ( see above ) . At the same time, a different stabilizer was used (see above ) and the odor warning substance was changed . From 1930 onwards, the specification of 5% chloropicrin as an odor warning substance appears several times 125), 126), 127), 128) . From 1943, bromoacetic acid methyl ester was reported as an odor warning substance 129), 130) . In 1943 it is also reported “when inquiring at the Degesch company in Frankfurt a . M. _, to what extent irritants are added to the hydrocyanic acid, the latter stated that the irritant addition is not always 2%, but depends on the respective stocks” 131) . The amount of warning or The use of irritants in the production of Zyklon B was gradually reduced during the course of the war; In 1943, it was partially dispensed with entirely, since it was not provided for by law 132) . In some cases attempts were made to use irritants such as ethyl chlorocarbonate and methyl cyanoformate instead of bromoacetic acid esters, which were in short supply 133) .
However, deliveries of Zyklon B without an odor warning substance had been commercially available much earlier, as can be seen from a report in the 1941 journal for hygienic zoology on an incident in 1924 134) . To the author's knowledge, it often happened that the disinfectors involved in direct contact with the production facility in Dessau received details of specific deliveries, e .g . B. _ agreed to deliver a batch of Zyklon B without an odor warning substance directly through official channels .
At the end of the explanation of odor warning substances for Zyklon B, reference is made to summary information about the most important odor warning substances, methyl bromoacetate, cyanogen chloride, methyl chlorocarbonate, chloropicrin and cyanogen bromide 135) .
In Table 3 below, an attempt is made to reconstruct from the above-referenced scientific specialist literature which odor warning substance was used in what quantity at different times for Zyklon B.
Table 3 Odor warning substance for Zyklon B 1922 – 1945 reconstruction
Illustration not included in this extract
Chapter 6 c The tin cans
In the introduction it was already mentioned that Zyklon B was packaged in tin cans . In detail, there were special features that u . a . reflected in two patents of DESCH for storing and transporting Zyklon B in tin cans 136) , 137) . The first patent relates to technical measures during filling to reduce the internal pressure after closing, the second relates to lining tin cans and lids with chlorinated rubber in order to increase gas tightness and make the cans more resistant to the odor warning substance chloropicrin they contain .
“The tin cans that serve as containers for Zyklon B are sealed exactly like tin cans by simply flanging the bottom and lid with a thin rubber seal in between . ' writes G. Peters in a summary 1933 138) . He goes on to say that the rubber material and sheet metal thickness are different from regular food cans . The metal thickness is 0.4 mm, which makes closing the can more difficult, but ensures the required gas tightness . From the further explanations of G .Peters that in the beginning normal rubber material (natural rubber?) and from about 1932 "a special inner coating" (chlorinated natural rubber?) was used, which then eliminated the initial sealing problems (caused by the odor warning substance chloropicrin) . There have probably also been further developments and changes in the manufacture and sealing of the cans over the course of time . A publication in 1930 speaks of soldered cans 139) . However, it is unanimously reported that these are tin cans in the style of normal food cans .
Conclusions about the size of the can can be drawn from the information about the contained amounts of Zyklon B. This information is different and partly contradictory . In 1928, a German publication mentions 200, 500, 1000 and 1200 g Zykan (CN) cans 140) . In the same year, a US publication gives details of cyan can contents of 20, 100, 500, 1000 and 1200 g 141) . This publication mentions total can weights of 200 g for the 20 g cyanide can, 400 g for the 100 g cyanide can and about three times the cyan content for larger cans 142) . Prices for Zyklon B ($/pound 0.90 – 1.00) can also be found here 143) .A publication in 1930 mentions cans with cyanide contents of 200, 500, 1000, 1200 g 144) . In 1931 a US publication mentions can contents of 15, 120, 480 and 1200 g 145) . In 1931 the following information existed for Zyklon Diskoids cans: total height 20.3 cm, diameter 10.2 cm . Filling 64 discoids, each 3.2 mm high, each loaded with 7.087 g of cyan, total content: 1 pound of cyan corresponding to 453.6 g . Total packaging: 48 cans in a box, each can protected against contact with an attached cardboard lid .Recent larger Zyklon discoids are also reported: Larger discoid cans: overall height 25.6 cm; Diameter 13 cm, filling 80 discoids, each 3.2 mm thick, each loaded with 14.17 g of cyan . Total content 1134 g or 40 ounces or 2.5 pounds of cyan . The external dimensions of the can can be estimated from this information: 1 pound cyan cans: height approx . 20.5 cm, diameter approx . 11.3cm; 2.5 pound cyan can: height approx . 26.0 cm, diameter approx . 14.3cm 146) . The discoids are able to bind 2.5 times their own weight in hydrocyanic acid .
Zyklon B cans containing 1.5 and 1.2 kg of cyanide played a special role in large-scale gassings . Therefore, an attempt should be made to estimate the dimensions of the can and to compare the estimates with more precise information . In a publication from 1930, cans are shown standing in front of a brick wall, the rows of bricks of which are in all probability 7.5 cm apart 147) . There are two can sizes with an estimated height of approx . 36 cm and approx . 28 cm . Both cans have an estimated diameter of approx . 16 cm .Leaving aside the differences in the outside and inside dimensions, the following volumes result: Large box approx . 7200 cm³, smaller can 5600 cm³ . The volume ratio shows that the large can was dimensioned for 1.5 kg of cyan and the smaller for 1.2 kg of cyan . As a comparison, you can also use an illustration of different can sizes from 1933 148) .
In August 1944, doses of Zyklon B were examined by a Soviet-Polish commission of experts in KL Majdanek 148a) . According to this, the 1.5 kg cyan cans have the following dimensions: height 31.5 cm, diameter 15.4 cm, corresponding to a volume of 5700 cm³ . Also specified are the total can weight of closed cans (3750 g), the weight of the cans with carrier but without hydrogen cyanide (2320 g) and the weight of the empty cans . This results in: hydrocyanic acid 1430 g (approx . 1500 g), carrier 1720 g, bulk density of the carrier 320 g/l . This information probably corresponds to reality .
From the 1930 publication, the estimate for the 1.5 kg cyan cans was 7200 cm³ . According to the data of the Soviet-Polish expert commission from August 1944, the 1.5 kg cyan cans had a volume of 5700 cm³ This difference can be explained: the cans published in 1930 come from a time before that . At that time, the carrier material had not yet been optimized . The bulk densities were higher (in some cases 340 – 450 g/l (see Chapter 6 a, Table 1) . The carriers of that time were heavier and absorbed less hydrocyanic acid, more carrier in a larger volume was needed for the same amount of hydrocyanic acid .
The carrier examined by the mixed Soviet-Polish commission had a bulk density of 320 g/l and contained 1500 g of pure hydrogen cyanide, corresponding to 1603 g of a mixture of active ingredient hydrogen cyanide in 1720 g of carrier . Presumably, this carrier had a similar composition to test mixture 4 in Table 2, Chap . 6a .
In the final years of the war, some of the cans were reused due to a shortage of materials . To do this, the rim of the empty cans was cut off and the cans were resealed . This resulted in somewhat shortened doses and also somewhat reduced hydrocyanic acid content .
Various simple and efficient methods were used to open the cans . In the simplest case, a hammer with a blade attachment was used, with which a 3.8 cm opening could be made in the cans with one blow of the hammer . Cans with a content of 1200 g of cyan with two such openings could be emptied in 15-20 seconds 149) . Opening works similarly with the help of opening scissors with about 10 teeth . They are placed on the can and a ring of about 10 holes is made in the lid of the can with one or more blows with a hammer 150) .
Illustration not included in this extract
fig . 13 Bibliography 150)
For a larger number of cans, devices were used for opening, with which one could open a can very quickly by simply pressing down a lever 151), 152) .
Illustration not included in this extract
“Zyklon cans are opened outside the building to be disinfested and rubber capped . For this work outdoors, the m suffices . E. _ - Society's device (mouthpiece with insert, pinched nose . "
Illustration not included in this extract
fig . 14 Bibliography 151), 152)
In half an hour you could open 100 cans with it 152) .
When used in circulatory disinfestation chambers 153), 154) , the cans are placed in a device built into the gas line – so-called . Cyclone generators - engaged . The inserted cans are then perforated 155), 156), 157), 158) by turning an externally operated crank . This takes place in a closed system so that there is no risk of poisoning for the operator . After switching on the circulating air, the hydrogen cyanide is then expelled with the air flow passing through 159) .
Illustration not included in this extract
fig . 15 Circuit disinfestation chamber (for cyclone) Fig . 17 cyclone generator
Illustration not included in this extract
Figures 15, 16 and 21 show the piping installations of closed-loop disinfestation chambers . Figures 17, 18, 19, 20, 21, 23 and 24 show details of the so-called cyclone generators .
A new procedure for chamber permeation
Illustration not included in this extract
Loading and unloading of the shown in Fig . Four-way switch shown for smaller cyclone carburetors . Chambers with built-in automatic can opener .
fig . 19 List of sources 156) Fig . 20 Bibliography 157)
Illustration not included in this extract
Mobile device for degassing cyclone cans with circuit arrangement .
fig . 21 Bibliography 158)
Illustration not included in this extract
fig . 22 Bibliography 159)
Left: transport trolley, carrying capacity approx . 15 Outfits . Two such cars
are pushed into a cell one behind the other to fill the 10 cbm space
to fill .
Right: Arrangement of the rebreathers in the cell (the numbers correspond to the notes in Fig . 2; also H = hand wheel for actuating the four-way switch and can opener from the outside . V = steam valve for the heating unit) .
Illustration not included in this extract
Insertion of the poison gas can in a carburetor, which is then closed gas-tight and circulated air flows through it .
fig . 23 Bibliography 160)
Illustration not included in this extract
The two cyclone gasifiers in the apparatus room in the shunt of the circuit line
fig . 24 List of sources 161)
The above doses are summarized in Tables 4 and 5 below .
Table 4 Cans for Zyklon B, shell soldered, cover seamed. reconstruction
Information about the doses
Illustration not included in this extract
Table 5 Cans for Zyklon discoids, shell soldered, lid seamed.
Information about the doses
Illustration not included in this extract
1) H: Height of cans
Ø: diameter of the cans
Chapter 6 d Transport regulations and overall packaging
The overall packaging includes everything that is required to put together a package that is ready for sale and dispatch . With Zyklon B, several cans are put together in a box . Criteria for this are the applicable transport regulations . A 1993 regulation on the transport of dangerous goods by rail is decisive . (Railway Hazardous Goods Ordinance - GGVE) from 22 . 09 . 1985 with amendments 1986, 87, 90, 93 162) . (See also the corresponding Dangerous Goods Ordinance Straße 163).
Prussic acid is in dangerous goods class 6 . 1 .
In this regard, recital 603 of the GGVE states: “Point 1 hydrocyanic acid must be packaged:
a) When completely absorbed by an inert porous mass, in strong metal receptacles not exceeding 7.5 liters capacity, placed in wooden boxes so that they cannot touch one another . Such a composite packaging must meet the following condition:
1. The vessels must be tested with a pressure of 0.6 MPa (6 bar overpressure) .
2. The vessels must be completely filled with the porous mass . The porous mass must not collapse or form dangerous cavities, even after prolonged use, when subjected to vibrations and even at temperatures of up to 50°C . The filling date must be permanently marked on the lid of each container .
3 . The composite packaging must be tested and approved according to Annex V for packing group I . A package must not be heavier than 120 kg . "
Appendix V contains complicated detailed regulations on the type of packaging and the requirements for packaging, labeling, testing of the entire packaging, etc .. Essential details for hydrocyanic acid / Zyklon B are:
- The tin cans (inner packing) are packed with spacers in a wooden crate as outer packing .
- The wooden box is marked RID / ADR / OAI / 4C X / S / 98
Explanations:
RID / ARD: Abbreviation for International Rail Transport Agreement (RID) and International Road Transport Agreement (ADR)
OAI: Abbreviation for inner packaging, light gauge plate, non-removable lid .
4C: Abbreviation for outer packaging wooden case
X: Abbreviation for very toxic substance, packing group I.
S: Abbreviation for inner packaging
98: year of manufacture .
- Testing of the entire packaging: The following drop tests from a height of 1.8 m onto a fixed impact plate five times each:
Flat on the floor
Flat on top
Flat on one long side
Flat to one side
On a corner
After the drop test, the entire packaging must still be safe to transport, all individual cans must be leakproof at 1.75 times the hydrocyanic acid pressure at 50° C and pass a stacking pressure test .
A test report is kept by the competent authority . Today e.g. B. _ at the Federal Institute for Materials Testing in Berlin .
Before 1945, the responsibility was the Chemical-Technical Reichsanstalt in Berlin .
The transport guidelines of the railways were the same in all important points . In the relevant document from 1938, paragraph 403 156) :
Test pressure 6 bar at 50° C
Vessels must be completely filled with porous mass
Filling date must be stamped on the lid
Shipping box wall thickness at least 18 mm
No touching the cans
Overall no more than 120 l capacity of the cans, total weight of a box max . 120kg .
In the EVO document from 1938, the detailed information about the necessary danger labels can be found on page . 55 and 56 at recitals 420, 422, 423, 424, 426 and on p . 74 and 75 of Appendix II 164) .
Thereafter, labels measuring 148 x 210 mm, at least 74 x 105 mm with a skull and crossbones symbol must be affixed to the crates and to both sides of the railway carriages .
The bill of lading must state in italics and underlined in red:
"Hydrocyanic acid with not more than 3% water, completely absorbed by a porous mass"; also "Storage separately from food and beverages" and "Condition and packaging comply with the provisions of Annex C to the EVO" .
The last sentence on the bill of lading is the confirmation that this regulation is met, according to which the hydrocyanic acid must contain a suitable stabilizer . (Recital 401)
Before 1933, the cans with 1500 g CN per can had a diameter of approx . 16 cm and a height of approx . 36 cm . They weighed about 4.5 kg per can and had a capacity of about 7.2 l per can (see chapter 6c) . The total capacity of all cans in a box was not allowed to exceed 120 l . A box therefore probably contained 16 such cans . If you arrange them in length and width 4 x 4 pieces, the approximate outer dimensions of the box are 80 x 80 x 40 cm, a total weight of 85 - 90 kg and a total capacity of the 16 cans of approx. 115 l .
In the case of cans with a smaller capacity, a box contained correspondingly more individual cans .
From cans with 1 pound each CN-Zyklon-Diskoids were z . B. _ packed in a box 48 pieces 165) .
Chapter 7 Features and handling of Zyklon B
The previous sections show that Zyklon B was neither liquid nor crystalline, but rather a solid, gritty, whitish to reddish-brown product in which a liquid mixture with hydrocyanic acid as the main component and with hydrocyanic acid stabilizers, tear gas-like odor warning substances and Impurities from the production of hydrocyanic acid were bound as secondary components in the semolina-like carrier, similar to water absorbed in blotting paper .
It was packaged in individual tin cans of various sizes, which were largely identical to common tin cans . The cans had to have a date of manufacture stamped on them because they were required to be used within a year . The quantity stated on the label referred to the cyanide (CN) content . Solid wooden crates, in which the cans were firmly packed with spacers, served as outer packaging for several cans for shipping . For safety reasons, most of the details, such as the purity of the hydrocyanic acid, the addition of stabilizers, the type of carrier, cans, labels, outer packaging were regulated by law or monitored by the Chemical-Technical Reichsanstalt .There was only room for maneuver for a few details such as the type and quantity of the odor warning substance and the size of the can (if less than 1.5 kg CN) .
For use as a pesticide, the cans were opened with gas masks and the gritty product was spread in a thin layer on paper pads . Then the relevant rooms were approx . Kept sealed for 24 hours or more . The hydrocyanic acid gradually escaped from the spread product, depending on the circumstances in approx . ½ hour and half and in approx . 2 hours 95% . After fumigation, the almost hydrocyanic acid-free carrier was disposed of safely, and it had to be well ventilated for 10-20 hours and objects such as beds had to be specially treated .Then it had to be confirmed by means of a prescribed hydrogen cyanide residual gas certificate that the rooms could be safely entered again . The authority to train state-certified disinfectors to use Zyklon B was restricted to very few companies and organizations and was strictly regulated . All details of handling were also strictly regulated 166), 167) 168).
There are no reports of accidents caused by poisoning with hydrocyanic acid when transporting Zyklon B. There are several reports of poisoning caused by inhaling hydrocyanic acid when handling Zyklon B 169), 170), 171), 172) . Of particular interest here are three reports, one of the poisoning of about 40 women who began work in a large mill 25 hours after deaeration began 173) , another of fatal poisoning of a disinfectant by prussic acid poisoning as a result of skin absorption 174 ) and a third, according to which one man died during a ship fumigation and another was seriously poisoned because the responsible disinfector had released the rooms after ventilation for too short a time 175) .
Chapter 8 The production
Dr. _ H. _ Reichardt and Dr. Julius Bueb in Dessau registered the first patent for the production of cyanide compounds from stillage (a waste product from sugar production) in 1894 176) .
Further patents followed on a furnace for the production of cyanide compounds 177) , on the conversion of stillage gases into cyanide compounds 178) , the production of cyanide compounds from stillage 179) , the manufacture of cyanide compounds from carbonization gases 180) , manufacture of cyanide compounds and ammonia by overheating stillage gases and other gases 181), 182) . The patents up to about 1900 were all registered by Julius Bueb in Dessau . From 1900 to around 1910 the "Chemische Fabrik Schlempe", Frankfurt/Main is named as the inventor, from 1910 it is the Deutsche Gold- und Silber-Scheideanstalt, before . Roessler in Frankfurt/Main .From 1913 to 1918 there are a number of patents which build on and improve upon the above patents . Inventors are now foreign and German authors .
Inventors of note here are Dr . Franz Muhlert, Göttingen and above all the German Gold and Silver Separation Institute, which registered a large number of patents at the time . Patents that are important for Zyklon B are now also appearing, e .g . B. _ Methods to make hydrogen cyanide more durable, to store, are claimed for activated carbon and porous substances such as kieselguhr and cork powder 183), 184), 185), 186), 187), 188) .
The 1925 patents describe processes and chemicals for preserving hydrocyanic acid incorporated into diatomaceous earth .
In 1929 there is still a patent from Dessauer Zucker-Raffinerie GmbH 189) .
After 1930 practically no more patents of the type described above appear . Patents for the continuous production of hydrogen cyanide from hydrocarbons and ammonia in the gas phase at high temperatures and with catalysts now dominate the field . The large-scale processes for the production of hydrocyanic acid that are customary today emerged from them . Hydrocyanic acid is still used today, among other things, as a precursor for the production of fibers and complexing agents (components of detergent) . The method according to L is an example . Andrusov called 190) .
At the beginning of the 1920s, large-scale processes for the production of hydrocyanic acid had not yet been tested in practice, and the Zuckerraffinerie GmbH Dessau together with Chemische Fabrik Schlempe and the German Gold and Silver Cutting Institute in Frankfurt had a 25-year tradition of patents for the production of hydrocyanic acid and cyanides . So it is not surprising that in 1922 the production of Zyklon B did not start in an IG Farben factory, but in the Zucker-Raffinerie GmbH in Dessau .
The following is a technical description of the production of hydrocyanic acid and Zyklon B as it stood between 1940 and 1945 in Dessau, insofar as this is possible on the basis of the available documents and information . Two pictures of the hydrocyanic acid/Zyklon B factory before and after 1945 make it easier to reconstruct the process .
First, a pamphlet “50 years ago . Der Neustart der Desssau Industrie im Jahres 1945" in the city of Dessau 191) , with a photograph of the part of the sugar refinery in which hydrocyanic acid and Zyklon B were produced before 1945 .
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Second, a photocopy of the same part of the sugar refinery from about
1965 in the company brochure of the VEB Gärungschemie Dessau with the title "100 years of chemistry in Dessau" .
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If you compare these two photographs, you can see that the structural arrangement is the same down to most details . You can also see changes, e.g. B. _ before 1945 a larger cooling tower of older design; after 1945 two newer designs . This leads to the conclusion that either little or no bomb damage affected this part of the factory, or that it was rebuilt largely true to the original . Therefore, one can further conclude that the production process before 1945 and after 1945 was completely or largely identical .
The manufacturing process that was used between 1951 and 1968 for the successor product to Zyklon B "Cyanol" is described below .
This is credible technical information from the VEB fermentation chemistry, which the author believes cannot be doubted . As far as this can be checked, they correspond to the information in the patent and technical literature . For example, the 12 cyanizing furnaces that existed between 1951 and 1968, in which the gas was heated to about 800° C, were largely identical to the furnace design as described in the patent by Reichardt and Bueb in 1895 193) .
Misinterpretations and errors cannot be ruled out with absolute certainty . However, after careful research, the author assumes that the following description of the production process after 1951 applies almost completely to the production process before 1945 in all essential details .
The production process is illustrated below by individual block diagrams .
Block diagram 1 Development of thin stillage in a sugar factory:
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Block diagram 2 shows the conversion of the thin stillage into smoldering gas and then into superheated "cyanized" smoldering gas containing gaseous hydrocyanic acid, ammonia and other gaseous products such as carbon monoxide and methane .
Block diagram 2: conversion of thin stillage into hydrocyanic acid
Illustration not included in this extract
The process according to block diagram 3 is the processing of the cyanized superheater gas . It is characterized by negative pressure in all gas-carrying parts, which is maintained by a large suction/pressure fan at the end (power approx . 0.5 MW) . This ensures that no gas containing hydrogen cyanide escapes . On the pressure side of the blower, the gas flow, now cleaned of NH3 and HCN, is conveyed into the smoldering furnace and burned there to generate heat .
Block diagram 3: processing of the cyanized superheater gas
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Block diagram 4 Working up of a water/cyanic acid mixture as obtained according to block diagram 3 .
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Block diagram 5 Filling of carrier and hydrocyanic acid in cans
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The bottling takes place under a fume cupboard in the manner of conventional laboratory fume cupboards with 4 adjacent 1 m wide sliding windows .
There are air intake openings in the upper part of the hoods . A 150 l HCN storage vessel is installed at the top of the hood A1 . In fume cupboard A2, two volume measuring vessels are connected to the HCN storage vessel via lines at their inlet and connected to a suctioned-off outlet opening at their outlet . Cans for filling can be placed under these outlet openings by pedal operation . An employee stands in front of the trigger A2 . By operating the manual valves H1 to H7, he alternately fills a can with the required quantity of hydrocyanic acid via the volume measuring vessels G2 and G3 on the left and on the right side and pushes it to the right under trigger A3 .
A second employee stands in front of prints A3 and A4 . For the production of cyanol, he prepares properly measured stacks of filter paper discs under hood A3 . He carefully places a prepared stack of filter paper discs in the can partially filled with hydrogen cyanide and, after a short waiting time, closes it with a simple can sealing device such as that used in e.g. B. _ used for sausage and meat preserves . The employees only work standing up . This was mandatory for safety reasons, so that they could flee the workplace in the event of an incident .
During filling, ethyl bromoacetate is continuously added dropwise via a manually controlled valve to storage vessel G1 in an amount corresponding to about 2% of the hydrocyanic acid . About once an hour, oxalic acid is added to vessel G1 as a concentrated aqueous solution in an amount that corresponds to about 0.1 - 0.2% oxalic acid based on hydrocyanic acid .
The sealed cans are loaded onto trolleys and stored overnight in a heating cabinet at 35°C . The next morning, cans with a bulging bottom or lid are sorted out . Then an employee sits down and checks the cans for leaks . To do this, he rotates them on a small apparatus placed between his knees and holds a piece of moist litmus paper to the lid of the rotating can . Cans in which the copper acetate benzidine paper discolours are sorted out . Only then do the cans go into the packaging .
In the book by J. Kalthoff and M. Werner "Die Händler des Zyklon B" is an illustration of the primitive manual filling according to scheme 6 and an illustration of the trolley on which the cans were stored overnight in the heating cabinet 194) .
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"Filling at the manufacturer"
fig . 27 List of sources 194)
Bottling of hydrogen cyanide for the production of cyanol
Illustration not included in this extract
fig . 28 Bibliography 194)
Zyklon production in Dessau . Checking the tightness of
Zyklon cans by heating in a "test channel" .
Chapter 9 Manufacturers of Zyklon B and carrier
Manufacturer of hydrocyanic acid and Zyklon B.
Hydrocyanic acid for Zyklon B and the commercial product Zyklon B were produced at the Dessau sugar refinery . It was founded in 1871 as the "Dessauer Aktien-Zucker-Refinerie" . In 1895 Reichardt and Bueb granted a patent for the production of cyanide compounds from molasses residues 177) . At that time almost 900 people were employed . In 1895 the company was converted into a GmbH . The "Strontian and Potash Factory Roßlau" was a branch . Production of sodium cyanide and potassium cyanide began before World War I.In 1921 there was a further change in the legal position through the founding of the "Dessauer Werke für Zucker und Chemische Industrie AG" while retaining the "Dessauer Zucker-Raffinerie GmbH", whose shares were almost 100% in the hands of the AG . In 1924 Zyklon B production began . The wood hydrolysis was set up in 1935 and the production of fodder yeast in 1942 . In 1945 the AG owned majority stakes in various sugar factories and chemical works . 1,500 workers and employees were employed in the Dessau and Roßlau parts of the company . In 1945, the Dessau parent company was reduced to approx . 70% destroyed .
The entries in the Reich address book from 1940 read:
1. Dessauer works for sugar and chemical industry AG
2. Dessauer sugar refinery GmbH
Both addresses: Dessau, Asnische Strasse 90 a .
After 1945, the legal situation initially remained the same . The old board continued to run the business . A plethora of problems arose in the post-war years . In mid-1949 the condition of the plant was so devastating that the previous management was arrested . From 1947 the Soviet military administration intervened, sometimes with contradictory measures . On 01 In July 1948, the plant was transferred to "public property" and designated as "Dessauer Zuckerraffinerie" with a branch "Strontian- und Potash Factory Roßlau" . It is reported that stillage gassing was already operational again in 1946 195) .This is an indication of minor war damage in this part of the factory .
Production and administration were reorganized in 1950/1951, and 1952 ended with a profit for the first time . In 1951, production of cyanol, the successor product to Zyklon B (see Appendix 2), and of sodium cyanide resumed . The company was renamed VEB-Gärungschemie . This name was retained until some time after the turn of 1989/90 . Alcohol, carbonic acid, fodder yeast and barium compounds were produced . In 1991 the production of barium compounds was abandoned .
Manufacturer for the carrier material for Zyklon B.
The carrier was bought in like other ingredients for Zyklon B (e.g. odor warning substance, stabilizer) .
In the specialist literature cited here, there is no indication of where the company "Dessauer Werke für Zucker und Chemische Industrie" bought the carrier material that it needed for the production of Zyklon B. The author is convinced that only Rheinhold & Co. United Kieselguhr und Korkstein-Gesellschaft mbH”, works in Coswig / Anhalt . The reasons for this belief are the details about the carrier described in Chapter 6. Another reason is the inventory list of Rheinhold & Co, Coswig / Anhalt plant on 31 . 12 . 1945:
Arguments for Rheinhold & Co Coswig as a supplier of the carrier material for Zyklon B according to Chapter 6:
- The writings "WSW-Kalender" and "WSW-Tabellarium" by the company Rheinhold & Co, in which the material designations "Lambda-Material" and "Dia-Material" are found, agree in the point with the technical literature, where these designations for the carrier material for Zyklon B 196) .
- The existence of the Klieken / Anhalt kieselguhr pit (halfway between Coswig and Dessau), where before 1945 kieselguhr was mined for Rheinhold & Co, Coswig plant .
Arguments for Rheinhold & Co Coswig plant as supplier of the carrier material for Zyklon B according to the inventory as of 31 . 12 . 1945 of the Coswig plant (see partial copy in Appendix 1):
- There are numerous “Dia” products and all the raw materials for manufacturing the carrier for Zyklon B (gypsum, kieselguhr K150, corn starch powder) .
- The proportions of these three ingredients in the inventory (gypsum: 12000 kg, kieselguhr K 150: 14000 kg, corn starch powder: 1000 kg) correspond almost exactly to the composition of the carrier reconstructed here (Chapter 6, recipe 4 in Table 2) .
- The inventory lists finished products with the designation "Erco", and in the specialist literature from 1933 the designation "Erco" stands for the carrier material for Zyklon B 197) .
- The designation of the kieselguhr with the prefix "K" points to the Klieken / Anhalt kieselguhr mine .The number 150 probably means the bulk density .
All in all, it follows that Rheinhold & Co, Coswig / Anhalt plant, supplied the carrier material for Zyklon B to the Dessauer Werke für Zucker und Chemische Industrie, Dessau plant .
As an addendum, it should be noted that after the fall of communism in 1989/90, the Rheinhold & Co factories in Coswig were shut down, the Klieken kieselguhr pit is no longer in operation and the remaining activities of Rheinhold & Co were taken over by Rheinhold & Mahla, Munich .
Chapter 10 The Sale of Zyklon B
The sale of Zyklon B was the task of the German Society for Pest Control mbH (DESCH), Frankfurt a . M. _ , Weissfrauenstrasse . 9 with its two regionally responsible main agencies Heerdt - Lingler GmbH . , Frankfurt a . M. _ , Hermann-Göring-Ufer 3 for West and South Germany and Tesch and Stabenow, International Society for Pest Control mbH, Hamburg for Germany east of the Elbe . Different addresses are given for Tesch and Stabenow in Hamburg: In 1936 the address in Hamburg was Ballinhaus 198) , in 1942 it was: Meßberghof 199) .
Until the end of production due to the war, there was a storage facility for Zyklon B in the sugar refinery in Dessau, which was set up by DESCH and was only under the control of DESCH and not the sugar refinery . The company DESCH was solely responsible for the entire shipment of Zyklon B.
In 1927 it was reported that this company, alongside the Reichswehr, the Navy and the company Georg Dreyer & Co. , Frankfurt a . M. _ (general representative of DESCH for the Department of Plant Protection ) has the right to use hydrocyanic acid for pest control in Germany . Unauthorized use of the hydrocyanic acid process was punishable by imprisonment for up to one year and/or a fine of up to 10,000 RM 200) .
According to the Reichsgesundheitsblatt from 1942, only the companies DESCH, Heerdt-Lingler and Tesch & Stabenow are authorized to provide training in the use of hydrocyanic acid for pest control 199) . Zyklon B was mainly advertised in trade journals . Some examples are shown in the figures below 201) – 204) .
A detailed documentation about the sales product Zyklon B, its history, which goes back to the First World War and to Prof. Fritz Haber, Head of the KWI for Physical Chemistry and Electrochemistry, Berlin, can be found in the book by J . Kalthoff and M. Werner 132) . The book contains many revealing details from the archives of the Hamburg sales company Tesch & Stabenow, which was responsible for deliveries east of the Elbe . Main content is trading with Zyklon B . The book contains detailed descriptions of the trading companies involved, but also information about the production sites in Dessau and Kolin (Bohemia) .In the appendix, the book contains a clear chronological table of the history of the Tesch & Stabenow company, an informative chemical glossary, an alphabetical list of references, detailed photo credits and a valuable index . For further details on the sale of Zyklon B, reference is made to the very well researched and richly illustrated book by Kalthoff and Werner 132) .
Illustration not included in this extract
fig . 29 Advertisement for Zyklon B Bibliography 201)
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fig . 30 advertisement for Zyklon u . a . bibliography 202)
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fig . 31 Advertisement for Zyklon u . a . Bibliography 203)
Illustration not included in this excerpt Illustration not included in this excerpt
fig . 32 Advertisement for Zyklon u . a . fig . 33 Advertisement for Zyklon u . a List of sources 204) List of sources 204)
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fig . 34 Advertisement for Zyklon u . a . bibliography 204)
Chapter 11 summary
This work attempts to collect factual information about the Zyklon B product, which was of great importance between 1922 and 1945 because it was a modern, technically improved commercial product for pest control with hydrocyanic acid at the time, and because, according to witness statements, it was used as a murder weapon in the last years of the Second World War was used for the mass gassing of people .
In the introduction, Chapter 1, this project is explained .
Chapters 2 and 3 summarize information about the components carrier (then kieselguhr) and the mixture of hydrocyanic acid and active ingredients for the early days of Zyklon B (about 1922 - 1930) .
Chapter 4 provides a historical outline of the use of hydrocyanic acid to combat pests from 1877, from the use of sodium cyanide / sulfuric acid to the Zyklon B process .
Zyklon B market development is described in Chapter 5 .
Chapter 6 entitled "The Zyklon B concept" contains details for the period 1922 - 1945 about the carrier, the hydrocyanic acid mixture, the tin cans and the overall packaging with reconstructed tables of the changes in this period (Tables 1, 2, 3, 4, 5) . Information about the carrier substance was collected particularly extensively and carefully because there is little concrete information about it in the specialist literature . Tables 1 and 2 make it possible to determine the composition of the carrier 1931 - 1945 with high probability and to describe it with the test mixture 4 in Table 2, which is also confirmed in Chapter 9 . Table 3 relates to the odor warning substance, Tables 4 and 5 to the tin cans. For the sake of completeness, details on transport regulations and the overall packaging are included in Chapter 6 .
Chapter 7 concerns properties and handling of the commercial product Zyklon B.
Chapter 8 on the production of Zyklon B is a reconstruction from patent specifications, literature references and the author's own research in Dessau .
The process is described in terms of process technology and chemistry using 5 block diagrams for production and a diagram for filling cans .
Chapter 9 deals with the manufacturing companies for Zyklon B, Dessauer Werke für Zucker- und Chemische Industrie AG, and for the carrier material, Rheinhold & Co United Kieselguhr and Korkstein-Gesellschaft mbH, Coswig / Anhalt plant (Rheinhold & Co) . Here the missing evidence in the cited specialist literature is provided that the company Rheinhold & Co, works in Coswig / Anhalt manufactured the carrier material for Zyklon B and delivered it to Dessau . With the help of the inventory list of this company as of 31 . 12 . This is substantiated in Appendix 1 in 1945 .