The Nazi's used Gas vans as a way of killing their enemies. The vans were fitted with special airtight containers. The vans were packed with Jews and with few others who were considered enemies. The Nazi's used carbon monoxide to kill all who were in the back of the van. The carbon monoxide wasn't killing thier enemies fast enough though, because when the vans reached the burial sites some of the victims would still be alive gasping for air. This created the need for a more effective way of killing their enemies in large quantities. That is where Zyklon B comes in. Zyklon B is Hydrogen Cyanide, a highly poisonous gas manufactured by Degesch. Its purpose was to be used for the fumigation of buildings and the delousing of clothes. First tested on, and was found perfect for the mass killings planned for Auschwitz. Degesch manufactured three different types of solid carriers; Wood fibre discs, a reddish brown granular mass, and small blue cubes. Cubes were an easy form to use and were used for the gas chambers at Auschwits. The cubes were dropped into an airtight room through special shafts in the ceiling. The cubes would then vaporize, giving off a bitter like almond odor. When an enemy breathed in, the gas combined with red blood cells, and deprived the body of vital oxygen. This would first cause unconsciousness but this state lasted only for minutes before death came to the Nazi's enemy. The door had a peephole on it so that the Nazi's could see into the gas chamber and check to make sure no signs of life were detected before opening the doors. As a precaution the Nazi's wore gas masks as they went in and emptied out the gas chamber. The gas left blue stains on the inside of the gas chambers, which can still be seen today.