At Birkenau the disinfecting of clothes was done by boiling them; there was no disinfestation by gas. The gas used for killing people was prussic acid, also called ZYKLON B.
The quantities of gas used were as follows. For the two large gas chambers attached to Krematoria I and II is required two tins for each chamber. For the smaller gas chambers attached to Krematoria III and IV it required one tin for each chamber. The tins were cylindrical with a diameter of 20-30 centimetres and about 50 centimetres tall. To kill a chamber full of people required 3-5 minutes.