"The History of Chemical Warfare and the Current Threat"
Mark Thoman, M.D.

Until recently, chemical warfare was not a popular topic and most civilian and military healthcare providers did not seem very familiar with it. This was particularly obvious during Operation Desert Shield/Desert Storm when it became apparent that many healthcare providers knew little about the effect of chemical agents or the medical defense against them. The prevailing attitude of the military healthcare providers was that chemical agents would only be used with unprepared or unprotected groups such as the Hmong, Afghans, and Curds. They also believed that if chemical weapons were used, the outcome would be disastrous, defense would be impossible, and the casualty rate and loss of life would be high.

Subsequent to Desert Storm, however, medical personnel learned that medical defenses were possible and effective and chemical casualties could be saved and returned to duty and the mortality could be minimized. Historically, the first use of chemical weapons dates from at least 423 BC when allies of Sparta and the Peloponnesian War took an Athenian-held fort by directing smoke from lighted coal, sulfur, and pitch through a hollowed out beam into the fort. In succeeding centuries, smoke, flames, and a combination of sulfur, pitch, naphtha, lime, etc. were used to incapacitate an enemy.

Modern inorganic chemistry during the late eighteenth and early nineteenth centuries and the organic chemistry evolution in Germany during the late nineteenth and early twentieth centuries generated a renewed interest in chemicals as military weapons and also a spirited debate concerning the ethics of chemical warfare. During World War I, the Germans used the new, but as yet unreliable invention, the portable flame-thrower and the French employed riot-control agents for civilian crowd control, which they used in minor skirmishes against the Germans. These were largely ineffective, and the search for more effective riot-control agents continued throughout the war. German units released one hundred fifteen tons of chlorine gas from six hundred cylinders near Ypres, Belgium during the afternoon of April 15, 1915. Although the attack caused probably no more than eight hundred deaths, it was psychologically devastating to the fifteen hundred Allied troops who promptly retreated. The Germans were not prepared to take advantage of this victory, and Chlorine and its successors were doomed to play a tactical, rather than a strategic, role during the war. The British in response were ready to use Phosgene and Chloropicrin that were primarily damaging to the upper and lower airways. Both sides developed a variety of masks to prevent inhalation injury. Masks also had the potential to protect against Cyanide, which the French and British, not the Germans, also fielded to a limited extent during the war.

Sulfur Mustard was first used July 12, 1917. One attack alone caused twenty thousand casualties and generated a new series of problems. Mustard, a relatively non-volatile liquid, was persistent, compared to the previously used agent. Not only the air that the soldier breathed, but also the objects that he touched, became potential weapons. It was quite effective at low doses. It affected not only the lungs, but also the eyes and skin. The latent period of this chemical, with up to several hours, gave no immediate clue to the exposure as there had been with earlier agents. Masks had to be augmented by hot, bulky, chemical protective clothing for soldiers and protection for their horses.

Between World War I and World War II, the debate on Chemical Warfare continued in the United States and International forums. The 1925 Geneva Protocol, which was signed by all major powers except the United States and Japan, implied the prohibition of the first use of chemical and biological weapons. The treaty, however, preserved the right to use such weapons in retaliation for a chemical attack.

In the late 1930s, a German industrial chemist, Dr. Schroeder, searching for more potent insecticides, synthesized Tabun (GA), an extremely toxic organophosphorus compound. Two years later, he synthesized Sarin (GB), a similar, but even more toxic, compound. These were generally known as nerve agents. However, they were not used during the second World War, and some thought that Hitler, himself a casualty of Mustard Gas during World War I, did not favor the use, neither did his senior staff.

With the possible exception of Japan during attacks on China, no nation during World War II used chemical agents in the battlefield, although Germany deployed cyanide and perhaps other chemical agents in concentration camps.

The end of World War II did not stop the development, stockpiling, or use of chemical weapons, and during the Yemen War (1963 to 1967) Egypt, in all probability, used Mustard bombs in support of South Yemen against Royal troops in North Yemen. The United States used defoliants (Agent Orange) and riot-control agents in Vietnam and Laos, but it finally ratified the Geneva Protocol in 1975.

Chemical agents, like other substances, may exist as solids, liquids, or gases depending on temperature and pressure. Except for riot-control agents, which are solids that usually encounter temperatures and pressures, chemical agents in munitions are liquids. Following detonation of a munitions container, the agent is primarily dispersed as a liquid or aerosol, which is a collection of very small solid particles or liquid droplets suspended in a gas. Thus, Tear Gas, used for riot-control, is not really a gas at all, but rather an aerosolized solid. Mustard "Gas" and Nerve "Gas" do not become true gases even when hot enough to boil water at sea level.

Certain chemical agents, such as Hydrogen Cyanide, Chlorine, and Phosgene, may be gases encountered during warm months of the year at sea level. Nerve agents and mustards are liquid under these conditions, but they are to a certain extent volatile. That is, they volatilize or evaporate, just as water or gasoline does, to form an often invisible vapor. The tendency of the chemical to evaporate depends not only on the chemical composition, but on the temperature and air pressure, as well as other variables such as wind velocity, volatility and nature of the underlying surface with which the agent is in contact. The more volatile a substance is, the more quickly it evaporates and the less it tends to stay or persist as a liquid and contaminate terrain and material.

There are six types of agents which are generally considered Warfare Agents:

1. Lung damaging (pulmonary agents) include the WW I Phosgene. The remainder of these agents are conventional warfare rather than chemical weapons. They include, Perflurorisobutylene (PFIB) a product of Teflon combustion; HC smoke (a smoke containing Zinc) and oxides of Nitrogen (from burning munitions).

2. Cyanide has an undeserved reputation as a good warfare agent, however, its high volatility means that effective concentrations are difficult to achieve on the battleground even though high concentrations cannot be maintained more than a few minutes in open air. However, at high concentrations, it does kill quickly and potential agents are Hydrocyanic Acid (AC) and Cyanogen Chloride (CK).

3. Vesicants include Mustard (Sulfur Mustard), Lewisite (L), Phosynoxine (CX). Vessicants are so named because of the blisters they cause on the skin. These agents also can cause damage to the eyes and airways by direct contact and have other affects as well.

4. Nerve agents inhibit the enzyme Acetylcholinestrase and effects of the result of excess Acetylcholine. Nerve agents are GA (Tabun), GB (Sarin), GD (Soman), GF and BX.

5. Incapacitating agents include BZ, a Glycolate, anticholinergic compound related to Atraphine, Scopolamine, and Hyoscyamine and Agent 15, an alleged incapacity agent used by Iraq, that is likely to be chemically identical to BZ or closely related to it.

6. Riot-control agents have been used on the battlefield, although they are not considered a major threat today. The National Guard may encounter or employ them during civilian disturbances. The major ones are CS, which is used by law enforcement in the military, and CN (Mace), which is sold in devices for self-protection.

In summary, Chemical Warfare has had a very long history of use, and it is now in the forefront of every health professional's consideration because of the various incapacitating effects. Additional information may be obtained from various web sites, such as the Department of Defense.