HCNHydrogen Cyanide


STEL: 10ppm (Short Term exposure Limit - 15mina)

TWA: N/A (Time Weighted Average - N/A)


Alarm Recomendations
Rising Latching Alarms For Line Safety Applications

First Alarm: Second Alarm: Third Alarm:
4ppm 7ppm Optional

Hydrogen Cyanide Molecule

Hydrogen Cyanide is a colourless gas that smells slightly of almonds. It is extremely poisonous, because it binds irreversibly to the iron atom in haemoglobin, making it unavailable to transport the vital O2 to the body’s cells and tissues.


Hydrogen cyanide is a colourless or light blue liquid or gas. It is extremely flammable with an LEL of 5.6%, although this is far above the toxic level. It has a faint bitter almond odour but it is estimated that 20-40% of people are genetically unable to detect. Hydrogen cyanide is also known as prussic acid and hydrocyanic acid.

Hydrogen cyanide is an important industrial chemical and over a million tonnes are produced globally each year. It is used primarily in the manufacture of other chemicals and plastics and also as a fumigant to kill pests. Cyanide compounds are used for metal process including electroplating. Sodium cyanide is produced from hydrogen cyanide and is used to extract gold and silver from ores.


Exposure to low concentrations or small amounts may cause headaches, dizziness and nausea. Symptoms usually improve soon after removal from an exposure. At higher concentrations, a rapid loss of consciousness, coma or death may occur. People surviving a serious exposure may have long term effects from damage to the brain.

Click here to learn moreClipboard