Toxicity

Cyanide is known to be one of the most active poisons as it is readily absorbed by oral and dermal routes of exposure. The central nervous system is the primary target organ for cyanide toxicity. Short-term exposure to high concentrations (100-200 mg) produces almost immediate collapse, respiratory arrest and death.

The lethal dose for humans is 1 mg CN‾/kg. This means that a rice grain size of cyanide is sufficient to kill a human being. Concentrations of 0,03 mg CN‾/l cause the death of many fish species and at a concentration of 3 mg CN‾/l a river is considered dead. Chronic cyanide exposure may affect reproduction, physiology, and levels of activity of many fish species and may render fishing sources non-viable.

During the Second World War, cyanide was used in its gaseous form (Hydrocyanic acid) under the name of Zyclon B in the gas chambers of the Auschwitz and Maidanek concentration camps.