This pic is for Chris &#39;Tingles&#39; Matthews who said Hitler never used chemical weapons. A label from a canister of Zyklon-B. Zyklon-B (Cyclone) is a form or oxygen reactive Prussic acid used for delousing &amp; as a pesticide. From 1941 until the end of the war, it was used to kill humans in the gas chambers of many concentration camps. The warning odorant added for safety was left out of the canisters destined for use against humans. Zyklon-B is still available today in a variety of forms.