@izzythepush,
Concenring the science side of Zyklon B (its properties) there is this to consider:
_______________________________
If high concentrations of hydrogen cyanide are used, as in American execution chambers, death occurs in a period of 10 minutes or even later. During the process, the victim is therefore exposed to a high overdose concentration of hydrogen cyanide. Technically this is not possible with Zyklon B, since the Zyklon B carrier base releases the gas slowly (50% in 30 to 90 minutes, according to the temperature and relative humidity). The distribution of the gas throughout the chamber from a few sources of hydrogen cyanide only, and the absorption of the gas by the moist walls and the nearby victims would further delay the process. Killing all the victims in a few (less than five) minutes would be impossible. Even during the use of very large quantities of Zyklon B.
The ventilation system, if it existed, did not have the performance to clear the chambers in the time frame attested to. Assuming that the victims died quickly from the high concentrations of toxic gas, then the workers in the Sonderkommando would also have been killed by the gas. Working without gas masks equipped with a filter is totally inconceivable; at high concentrations of poison gas, even these are very unsafe. Heavy respiratory devices must be worn at concentrations of over 0.5 Vol.%, which would render the removal of the bodies much more difficult. Contamination through the skin must be expected during heavy work, involving perspiration, and due to the high concentrations of hydrogen cyanide on the skin of the victims. At the same time, such concentrations are sufficient to put a stop to the workers' ability to work (dizziness, nausea, etc.). Protective clothing is therefore required.