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