Zyklon B - was the trade name of a cyanide-based pesticide infamous for its use by Nazi Germany to kill human beings in gas chambers of exterimation camps during the Holocaust.
Zyklon B is a cyanide-based poisonous gas that interferes with cellular respiration. Specifically, it prevents the cell from producing ATP by binding to one of the proteins involved in the electron transport chain.
On September 3, 1941, around 600 Soviet prisoners of war and 250 sick Polish prisoners were gassed with Zyklon B at Auschwitz camp I; this was the first experiment with the gas.
According to Rudolf Höss, bunker 1 held 800 people, and bunker 2 held 1,200. Once the chamber was full, the doors were screwed shut and solid pellets of Zyklon B were dropped into the chambers through vents in the side walls, releasing the cyanide gas. Those inside died within 20 minutes; the speed of death depended on how close the inmate was standing to a gas vent, according to Höss, who estimated that about one third of the victims died immediately. Johann Kremer, an SS doctor who oversaw the gassings, testified that “Shouting and screaming of the victims could be heard through the opening and it was clear that they fought for their lives. When they were removed, if the chamber had been very congested, as they often were, the victims were found half-squatting, their skin colored pink with red and green spots, some foaming at the mouth or bleeding from the ears.”