Zyklon B

A commercial form of hydrocyanic acid (or a hydrogen cyanide) that vapourizes when exposed to the air, manufactured by the firms Degesch and Tesch/Stabenow, under patent from I.G. Farben, brought to Auschwitz in the summer of 1941 as a disinfectant and insecticide (for delousing purposes) but subsequently applied as a means of mass execution more efficient than the redirected-exhaust container trucks which were then in use. By the end of the war Degesch was supplying two tons of Zyklon-B (Cyclone-B) a month and Tesch another three-quarters of a ton. By then the gas had been used to exterminate an estimated six million prisoners, primarily Jews.

Prisoners were led into gas chambers which had been disguised as public showers. When they were all in the room, the chamber would be made airtight and Zyklon-B would be released into the air, vapourizing and giving off cyanide's characteristic bitter almond smell.

The vapours combined with red blood cells, resulting in oxygen starvation. The particular brand of Zyklon-B used by the Nazis in the death camps contained blue colouring and blue stains can still be observed today in untampered gas chambers.

Death came almost instantly to those located adjacent to the air vents through which the Zyklon-B was introduced; the entire chamber would have been dead within fifteen minutes. After a half-hour, forced ventilation was turned on and the Sonderkommandos would enter the room, removing gold teeth and cutting the hair from the women, after which the corpses were transported by elevator to the ovens where they were cremated.

Though the German companies that made and sold the gas to the Nazis claimed after the war that they were unaware of their product's potential as a means of human execution the gas had been used in execution gas chambers since 1920 in the USA, when its use began in an Arizona prison.

Zyklon B was the substance used by the Nazis to exterminate prisoners in the gas chambers.

It was manufactured, under the orders of the Nazi government, by the Flick Manufacturing Corporation. At the Nuremburg Trials the company were found guilty, the tribunal cited that that making a criminal weapon cannot be distinguished from using it.
(Perhaps this was how the character of 'Herr Flick' was named as such in 'Allo 'Allo?)

The use of Zyklon B came about through, more or less, trial and error. Earlier gassing techniques were attempted using the exhaust fumes from lorries, but these were found to be inefficient, so alternative methods were sought. The gas cannisters would be placed in a gap in the chamber walls, then pierced. The gas would then enter the chambers through shower heads, killing all within. The people who had to put the canisters would also die, thusly, this task was handed to the Jews.

Zyklon B was invented at the Kaiser Wilhelm Institute for Physical Chemistry in Berlin. Phosgene, Mustard Gas and Sarin were also invented there. It was originally a fumigant and rodenticide. It was used mostly to rid ships and builings of rats and mice. One of the main reasons it was used to exterminate Jews was because of its wide availability as a seemingly innocent pesticide. It killed by restricting or cutting off the supply of oxygen to the bloodstream.

Zyklon B is created by combining hydrocyanic acid with a porous carrier substance like wood pulp, or absorbant clay. This combination would usually be formed into pellets then sealed in canisters until they were ready for use.

SPECIFICATIONS FOR HCN
Name: HCN, hydrocyanic acid; prussic acid
Boiling point: 25.7 C / 78.3 F at 760 mm Hg
Specific gravity: 0.69 at 18 C / 64 F
Vapor density: 0.947 (air = 1)
Melting point: -13.2 C / 8.2 F
Vapor pressure: 750 mm Hg at 25 C / 77 F 1200 mm Hg at 38 C /100F
Solubility in water: 100%
Appearance: clear
Color: slightly bluish
Odor: bitter almond, very mild, non-irritating (odor is not considered a safe method of determining presence of the poison)

Hazards:
1. Unstable with heat, alkaline materials and water
2. Will explode if mixed with 20% sulfuric acid.
3. Polymerization (decomposition) will occur violently, with heat, alkaline material or water. Once started, reaction is autocatalytic and uncontrollable. Will explode.
4. Flash point: -18 C / 0 F
5. Autoignition temperature: 538 C / 1000 F
6. Flammable limits in air volume % lower 6 upper 41

info from various sources and www2 analysis sites.