Hydrogen cyanide is a colourless gas, which has a faint, bitter, almond-like odour. Its solution in water forms a weak acid, commonly known as hydrocyanic or prussic acid. Hydrogen cyanide melts at 140C and boils at 260C. It is stongly flammable and it is a potentially explosive hazard when mixed with air.
Read more
Common name: Formonitrile, hydrocyanic acid or prussic acid, HCN.
Use
The principal use of hydrogen cyanide is in the manufacture of organic chemicals that are used in producing synthetic fibres and plastics. It is also sometimes used in agriculture as a fumigant.
Releases to the environment
Hydrogen cyanide is found in small quantities in the natural environment, especially in a variety of plants. Most hydrogen cyanide is released through natural occurring processes, especially as biomass burning, and through industrial manufacturing activities such as electroplating, metal mining and metal cleaning processes. Another source of release is from cigarette smoking.
Impacts on the environment and human health
Hydrogen cyanide is very toxic to fish and other forms of aquatic life. Hydrogen cyanide generally does not bind to soils and may leach to the groundwater. Hydrogen cyanide is very toxic by ingestion, skin contact and by inhalation. The brain and the cardiovascular system are the main organs affected by hydrogen cyanide.
International actions
Hydrogen cyanide is on the EU-Commissions EPER list and listed in the PRTR Protocol under the Århus Convention.
CAS NO: 74-90-8