INTRODUCTION
Hydrogen cyanide is usually included among the CW agents causing general poisoning. Hydrogen cyanide has high toxicity and in sufficient concentrations it rapidly leads to death. At room temperature, hydrogen cyanide is a colorless liquid which boils at 26 degrees celcius. The most important route of poisoning is through inhalation.
Both gaseous and liquid hydrogen cyanide, as well as cyanide salts in solution, can also be taken up through the skin. Its high volatility probably makes hydrogen cyanide difficult to use in warfare since there are problems in achieving sufficiently high concentrations outdoors. On the other hand, the concentration of hydrogen cyanide may rapidly reach lethal levels if it is released in confined spaces.
The most important toxic effect of hydrogen cyanide is by inhibiting the metal-containing enzymes. One such enzyme is cytochromoxidase, containing iron. This enzyme system is responsible for the energy-providing processes in the cell where oxygen is utilized, i.e., cell respiration.
When cell respiration ceases, it is no longer possible to maintain normal cell functions, which may lead to cell mortality. Symptoms of cyanide poisoning vary and depend on, for example, route of poisoning, total dose and the exposure time.
If hydrogen cyanide has been inhaled, the initial symptoms are restlessness and increased respiratory rate. Other early symptoms are giddiness, headache, palpitations and respiratory difficulty. These are later followed by vomiting, convulsions, respiratory failure and unconsciousness.
If the poisoning occurs rapidly, e.g., as a result of extremely high concentrations in the air, there is no time for symptoms to develop and exposed persons may then suddenly collapse and die.