Chemical Warfare and Its Uses Chemical warfare is the use of natural and man-made toxic substances to incapacitate or kill an enemy. There are many different types of agents used in chemical warfare, some of which are mustard gases, nerve gases, psychotomimetic agents, tear gases, hydrogen cyanide, and arsines. All of which are very poisonous and lethal when exposed to humans in large amounts. Until the 20th century such warfare was primarily limited to starting fires, poisoning wells, distributing smallpox-infected articles, and using smoke to confuse the enemy. Today however, it is used as lethal combative. Mustard Agents Mustard agents are usually classified as 'blistering agents' owing to the similarity of the wounds caused by these substances resembling burns and blisters.
However, since mustard agents also cause severe damage to the eyes, respiratory system and internal organs, they should preferably be described as 'blistering and tissue-injuring agents'. Normal mustard agent, bis- (2-) sulphide, reacts with a large number of biological molecules. The effect of mustard agent is delayed and the first symptoms do not occur until between 2-24 hours after exposure. Mustard agent is simple to manufacture and can therefore be a 'first choice' when a country decides to build up a capacity for chemical warfare. Mustard agent was produced for the first time in 1822 but its harmful effects were not discovered until 1860. Mustard agent was first used as a CW agent during the latter part of the First World War and caused lung and eye injuries to a very large number of soldiers.
Many of them still suffered pain 30-40 years after they had been exposed, mainly as a result of injuries to the eyes and chronic respiratory disorders. In its pure state, mustard agent is colorless and almost odorless. The name was given to mustard agent as a result of an earlier production method which yielded an impure mustard-smelling product. Mustard agent is also claimed to have a characteristic smell similar to rotten onions. However, the sense of smell is dulled after only a few breaths so that the smell can no longer be distinguished. In addition, mustard agent can cause injury to the respiratory system in concentrations which are so low that the human sense of smell cannot distinguish them.
Symptoms of mustard agent poisoning extend over a wide range. Mild injuries consist of aching eyes with abundant flow of tears, inflammation of the skin, irritation of the mucous membrane, hoarseness, coughing and sneezing. Normally, these injuries do not require medical treatment. Severe injuries which are incapacitating and require medical care may involve eye injuries with loss of sight, the formation of blisters on the skin, nausea, vomiting and diarrhoea together with severe respiration difficulty.
Acute mortality arising from exposure to mustard agent is low. The dose needed to directly kill a person upon inhalation is, e. g., about 50 times larger than the dose giving acute mortality upon poisoning with the nerve agent so man. People who die after exposure to mustard agent usually do so after a few days up to one or more weeks. Arsines Among the arsenal of chemical weapons can be found mustard agent mixed with lewisite which is an aliphatic arsenic compound, 2-.
Pure lewisite is a colourless liquid. Solubility in water is approximately the same as for mustard agent but the volatility is much higher. Hydrolysis in water is faster than for mustard agent. Injuries caused by lewisite are similar to those caused by mustard agent. However, the mechanism of action for lewisite is different. Fromthe diagnostic viewpoint, an important difference is that symptoms in lewisite poisoning are not delayed and the irritating effect occurs immediately.
Skin damage is treated in the same way as after exposure to mustard agent. A specific antidote (BAL, British Anti Lewisite, ) gives good protection against local injuries to skin and mucous membrane. BAL also has effect against systemic poisoning. Hydrogen cyanide is usually included among the CW agents causing general poisoning. There is no confirmed information on this substance being used in chemical warfare.
However, it has been reported.