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Hydrogen Cyanide

Who is at risk?

Hydrogen cyanide is an important industrial reagent. It is widely used in industrial processes to manufacture various chemicals for use in plastic production and metal processing.

Hydrogen cyanide is also used in the pest control industry as fumigant.


Bitter almond odour


Hydrogen cyanide is one of the most rapidly acting poisons and exposure to small concentrations can be extremely dangerous.

Hydrogen cyanide interferes with the body's use of oxygen and has severe effects on the central nervous and cardiovascular systems.

Acute Exposure

Concentration Effect
135 ppm Rapid dizziness, nausea and difficulty breathing - endangering to life
100 - 200 ppm Low blood pressure and abnormal heart rhythm – lethal
300 ppm Immediate convulsions, loss of consciousness and death in minutes

NFPA 704 Signal

  Hazard Value Description
Health 4 Can be lethal.
Flammability 4 Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature.
Instability 1 Normally stable but can become unstable at elevated temperatures and pressures.
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