High Quality Content by WIKIPEDIA articles! Zyklon B (German pronunciation: ; also spelled Cyclon B or Cyclone 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 extermination camps during the Holocaust. The "B" designation indicates one of two types of Zyklon. The other was "Zyklon A" – a liquid pesticide which released hydrogen cyanide in a chemical reaction with water.