Zyklon B

Zyklon labels from Dachau concentration camp used as evidence at the Nuremberg trials; the first and third panels contain manufacturer information and the brand name, the center panel reads "Poison Gas! Cyanide preparation to be opened and used only by trained personnel"

Zyklon B ( German: [tsyˈkloːn ˈbeː] ; translated Cyclone B) was the trade name of a cyanide-based pesticide invented in Germany in the early 1920s. It consists of hydrogen cyanide (prussic acid), as well as a cautionary eye irritant and one of several adsorbents such as diatomaceous earth. The product is notorious for its use by Nazi Germany during the Holocaust to murder approximately 1.1 million people in gas chambers installed at Auschwitz-Birkenau, Majdanek, and other extermination camps.