The following information contains adaptations and excerpts from the US Army Center for Health Promotion and Preventive Medicine (USACHPPM) Tech Guide 244, The Medical NBC Battlebook.

General. Blood agents consist of hydrogen cyanide (AC) and cyanogen chloride (CK). The mucous membranes and the intact skin readily absorb both AC and CK. Initial symptoms are characterized by violent convulsions increased deep respiratory movements followed by cessation of respiration within one minute slowing of heart rate to death. High concentrations exert their effects rapidly; however, if the patient is still alive after the cloud has passed, he or she will probably recover spontaneously. Cyanogen chloride and cyanogen bromide after absorption reacts in such a way that hydrogen cyanide is eventually released. Their effects on the body are essentially similar to those of hydrogen cyanide but in addition, they also have local initial effects.

Chemical Properties.

a) The cyanogen compounds hydrolyze slowly in water with subsequent gradual loss of toxicity. They are readily oxidized by strong oxidants; e.g., potassium permanganate. Hydrogen cyanide has an affinity for oxygen and is flammable; hence, it is less efficient when dispersed by artillery shells.

b) Cyanogen chloride is only slightly soluble in water it dissolves readily in organic solvents. Cyanogen chloride's pungent, biting odor is marked by its irritating lacrimatory properties. Normally cyanogen chloride is non-persistent.

c) Cyanogen halides are rather poorly absorbed onto charcoal, especially if the charcoal is damp.

Medical Effects of Hydrogen cyanide (AC).

a) The cyanide ion forms a reversible complex with the respiratory cytochrome oxidase enzyme system, an enzyme system essential for oxidative processes within cells. This results in impairment of cellular oxygen utilization. The central nervous system, particularly the respiratory center, is especially susceptible to this effect and respiratory failure is the usual cause of death.

b) Treatment. Successful treatment for acute cyanide poisoning depends upon rapid fixation of the cyanide ion, either by methemoglobin (rnetHB) formation or by fixation with cobalt compounds. Drug treatments include, compounds producing Methemoglobin, Hydroxyocobalamin, and Dicobalt edetate. Any victim who is fully conscious and breathing normally more than 5 minutes after presumed exposure to cyanide agents has ceased will recover spontaneously and does not require treatment, cyanide being very rapidly detoxified in the body. Artificial resuscitation, though possible, is not likely to he helpful in the absence of drug treatment. First Aid Measures: the casualty should be removed from the source of hydrogen cyanide. Rescue workers should wear adequate individual protective equipment (IPE).

Medical Effects of Cyanogen Chloride (CK).

a) Cyanogen chloride acts in two ways: Its systemic effects are similar to those of hydrogen cyanide but it also has local irritant effects on the eyes, upper respiratory tract, and lungs. Cyanogen chloride injures the respiratory tract resulting in severe inflammatory changes in the bronchioles and congestion and edema in the lungs. Very low concentrations (e.g., 10-20 rng.min.m3) produce eye irritation and lacrimation.

b) Signs and Symptoms. The signs and symptoms caused by cyanogen chloride are a combination of those produced by hydrogen cyanide and a lung irritant. Initially, cyanogen chloride stimulates the respiratory center and then rapidly paralyses it. In high concentrations, however, its local irritant action may be so great that dyspnea is produced.

c) Treatment. Cyanogen chloride poisoning should be treated in the same way as hydrogen cyanide poisoning as regards to its cyanide-like effects. Pulmonary irritation should be treated in the same way as phosgene poisoning.

d) Course and Prognosis. Recovery from the systemic effects of cyanogen halide poisoning is usually as prompt as in hydrogen cyanide poisoning. However, a higher incidence of residual damage to the central nervous system is to be expected. Depending on the concentration of cyanogen halide to which the victim has been exposed, the pulmonary effects may develop immediately or may be delayed until the systemic effects have subsided. Early prognosis must, therefore, be guarded.

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