Ø     Holocaust à A form of HCN was used in the nazi gas chambers during WW2 called Zyklon-B.  Due to the confinement of the chambers used for gassing it was hard for the HCN to dissipate, creating a level of HCN that was lethal almost instantaneously.

Ø      Chemical warfare à The French used 4,000 tons of HCN in WW1, however, because the HCN gas was able to dissipate quickly it was very ineffective.  Hydrogen Cyanide was thought to have been used in the Middle East, although it cannot be confirmed.  Hydrogen Cyanide gas is very infrequently used in warfare because it dissipates into the air to quickly for it to be deadly.  HCN spray is more often and more effectively used in warfare.

Ø     Spray à Although HCN does not work to well as a gas, the liquid form of HCN is very effective at killing people.  The liquid form of HCN can be absorbed through the eyes, pores, or any open cuts on the skin surface.  Once the liquid is absorbed into the body it causes instant death. 

Ø     Used to make Acrylonitrile, which is a base product for plastics, acrylic fibers, and synthetic rubbers.

Ø     Sodium Cyanide can be used for extracting gold from ore, silver from used film, and in other chemical manufacturing

Ø     Pharmaceuticals

Ø     Used commercially as a rodenticide and insecticide for fumigation enclosed spaces. 

HCN is important because it was used in one of the biggest attempted genocide in the world, it can be used in warfare, and it is used to make several everyday products such as Acrylonitrile and some pharmaceuticals.