The Gas Chamber at Krematorium I
Victims were led in through the door at the front left. To the right and near the top edge of the photo, ia another post-war reconstruction. Notice the rectangular dark area, one of the ceiling openings through which the blue crystals were poured from the rooftop by SS guards wearing gas masks as they were immediately activated on release from their canisters. Scrolling right to another doorway, you catch a glimpse of the furnace room. The poisonous agent, "Zyklon B", was used in Germany before and during the war for disinfection and pest extermination in ships, buildings and machinery. In Auschwitz it was used exclusively for sanitation and pest control until the end August of 1941. From that time it was also used as an agent of mass annihilation, first experimentally (on Russian POW's) and then routinely. Zyklon B consisted of diatomite, in granules the size of fine peas saturated with prussic acid. In view of its volatility and the associated risk of accidental poisoning, it was supplied to the camp in sealed metal canisters. The Zyklon used at Auschwitz was produced by the firm Degesch (Deutsche Gesellschaft für Schädlingsbekämpfung mbH), with headquarters in Frankfurt am Main and forming a part of IG Farbenindustrie.
For photo of Zyclon B canisters see: [link]