Introduction to Hydrogen Cyanide (HCN)

Hydrogen Cyanide (HCN) is a colorless and extremely poisonous gas that boils just above room temperature. With its distinctive bitter odor, it is often used as an inhalation rodenticide and human poison. Historical events such as World War I and II have used Hydrogen Cyanide as a poison and chemical weapon. However, it also has practical application uses, such as being the precursor to many chemical compounds ranging from polymers to pharmaceuticals.

Hydrogen Cyanide is a systemic chemical asphyxiant. It interferes with iron-containing respiratory enzymes and the normal use of oxygen by nearly every organ of the human body. This toxic gas can be rapidly fatal and can also mix with air to form explosive conditions within a facility. However, a large proportion of people cannot detect Hydrogen Cyanide; the odor does not provide adequate warning of hazardous concentrations. Proper monitoring and detection methods are absolutely necessary for any industry working with Hydrogen Cyanide.

Health Hazards

When present in high concentrations, Hydrogen Cyanide may produce these symptoms:

  • Headache
  • Dizziness
  • Eye, nose, throat, respiratory irritation
  • Coma
  • Pulmonary edema (excess fluid in lung tissue)
  • Seizure
  • Oxygen deficiency
  • Systemic toxicity
  • Death

Exposure Limits

When researching HCN gas detection solutions, facility managers should be aware of the following HCN exposure limits:

Exposure Limits Agency
10 ppm TWA OSHA PEL (General Industry)
10 ppm TWA OSHA PEL (Construction Industry)
10 ppm TWA OSHA PEL (Maritime)
10 ppm TWA ACGIH TLV
5 ppm TWA NIOSH REL
50 ppm NIOSH IDLH

Products for HCN Gas Detection

HCN Gas Detectors

For further product information for detecting HCN gas, contact your local Sierra Monitor sales representative.

Technology for HCN Gas Detection

Electrochemical Sensors

Electrochemical sensors are fuel cell-like devices consisting of an anode, cathode, and electrolyte. The components of the cell are selected so that a subject gas, allowed to diffuse into the cell, will cause a chemical reaction and generate a current. The cells are diffusion-limited, meaning that the rate of the gas entering the cell is solely dependent on the gas concentration. The current generated is proportional to the rate of consumption of the subject gas in the cell.

Learn more about the advantages of using Sierra Monitor's electrochemical gas sensor modules »