Zyklon B is an insecticide and it released HCN, Hydrocyanic acid - a gas. It usually comes in small pellets or disks and the HCN is what causes the death. Zyklon B is extremely poisonous to humans and it's used in the execution chambers in the US. There were two types of chambers in Auschwitz - those used for delousing and those for gassing and those for killing people on a massive scale. Hydrocyanic acid is a very weak acid and accordingly, it's salts dissolve in stronger acids. Even carbonic acid, which is formed as a reaction of carbon dioxide with water, will dissolve in Ferro-cyanide.
At Auschwitz, there was fifteen huge furnaces, each could incinerate three bodies in a span of forty-five minutes. 720 bodies in a twelve hour day were buried. In a single year, Krema II could burn a quarter of a million bodies, some bodies were also burned in massive pits. The ashes of the bodies was scattered around the fields, buried or dumped into rivers. Those who were seen as unfit to work, were immediately gassed. Some camps even used gasoline engines, therefore the persons to be executed suffer death from suffocation and not death by dozing off as planned.
Often the prisoners would have to wait outside in any weather. They'd have to give up their possessions: money, jewellery, even wedding rings and photos. The prisoners were left with one thing, their bodies. Men and women were forced to stand on stools in a room crowded with people, while their heads, armpits and other intimate areas were shaved by male prisoners and numbers were tattooed into each arm. The Auschwitz camps had barracks consisting of 62 bays with three roosts. The roosts were originally supposed to hold three people but Bischoff increased it to four. The barracks were originally designed to be horse stables. Some slept as many as eight people on each hutch level. The barracks were locked at night and were supplied with only buckets for toilets.
