Chemical Warfare
Chemical Warfare
Use of petroleum as a weapon during the Gulf War of 1991-1992
Controls over the use of chemical weapons
Terrorism and chemical weapons
Chemical warfare involves the use of natural or synthetic substances to incapacitate or kill an enemy or to deny them the use of resources such as agricultural products or screening foliage. The effects of the chemicals may last only a short time, or they may result in permanent physical damage or death. Most of the chemicals used are toxic to humans or plant life. Other, normally mild chemicals have also been intentionally misused in more broadly destructive anti-environmental actions, called ecocide, and as a crude method of causing mayhem and damaging an enemy’s economic system. The deliberate dumping of large quantities of crude oil on the land or in the ocean is an example.
Chemical warfare dates back to the earliest use of weapons. Poisoned arrows and darts used for hunting were also used as weapons in intertribal conflicts; they are still used for these purposes today in some cultures. In 431 BC, the Spartans used burning sulfur and pitch to produce clouds of suffocating sulfur dioxide in their sieges against Athenian cities. When the Romans defeated the Carthaginians of North Africa in 146 BC, during the last of a series of Punic Wars, they leveled the city of Carthage and treated the surrounding fields with salt to destroy the agricultural capability of the land, thereby preventing the rebuilding of the city.
The attraction of chemicals as agents of warfare is their ability to inflict mass casualties or damage to an enemy with only limited risk to the forces using the chemicals. Poisoning a town’s water supply, for example, poses almost no threat to an attacking army, yet can result in the death of thousands of the town’s defenders. In many cases, the chemicals are also undetectable by the enemy until it is too late to take action.
Chemical agents can be classified into several general categories. Some cause only temporary incapacitation. Examples included tear gas and pepper spray. Other agents cause violent skin irritation and blistering and may result in death. Some agents are poisonous and are absorbed into the bloodstream through the lungs or skin to kill the victim. Nerve agents attack the nervous system and kill by causing the body’s vital functions to cease. Still others cause psychological reactions, including dis-orientation and hallucinations. Chemical agents that attack vegetation include: defoliants, which kill plant leaves; herbicides, which kill the entire plant; and soil sterilants, which prevent the growth of new vegetation.
The first large-scale use of poisonous chemicals in warfare occurred during World War I. More than 100,000 tons (90,700 metric tons) of lethal chemicals were used by both sides during several battles in an effort to break the stalemate of endless trench warfare. The most commonly used chemicals were four lung-destroying poisons: chlorine, chloropicrin, phosgene, and trichloromethyl chloroformate, along with a skin-blistering agent known as mustard gas, or bis (2-chloroethyl) sulfide. These poisons caused about 100, 000 deaths and another 1.2 million injuries, almost all of which involved military personnel.
Despite the agreements of the Geneva Protocol of 1925 to ban the use of most chemical weapons, the United States, Britain, Japan, Germany, Russia, and other countries all continued development of these weapons during the period between World War I (1914–1918) and World War II (1939–1945). This development included experimentation on animals and humans. Although there was only limited use of chemical weapons during World War II, the opposing sides had large stockpiles ready to deploy against military and civilian targets.
During the war in Vietnam, the United States military used a nonlethal “harassing agent” during many operations. About 9, 000 tons (8, 167 tonnes) of tear gas, known as CS or o-chlorobenzolmalononitrile, were sprayed over 2.5 million acres (1.0 million ha) of South Vietnam, rendering the areas uninhabitable for 15-45 days. Although CS is classified as non-lethal, several hundred deaths have been reported in
cases when CS has been used in heavy concentrations in confined spaces such as underground bunkers and bomb shelters.
Poisonous chemicals were also used during the Iran-Iraq War of 1981-1987, especially by Iraqi forces. During that war, both soldiers and civilians were targets of chemical weapons. Perhaps the most famous incident was the gassing of Halabja, a town in northern Iraq that had been overrun by Iranian-supported Kurds. The Iraqi military attacked Halabja with two rapidly acting neurotoxins, known as sabin and tabun, which cause rapid death by interfering with the transmission of nerve impulses. About 5, 000 people, mostly civilians, were killed in this incident.
Rumors of stockpiled chemical and biological weapons were a factor behind the invasion of Iraq in 2003 by coalition forces under the leadership of the United States. Large-scale stockpiles were not found.
During the Vietnam War (1954–1975), the U.S. military used large quantities of herbicides to deny their enemies agricultural food production and forest cover. Between 1961 and 1971, about 3.2 million acres (1.3 million ha) of forest and 247, 000 acres (100, 000 ha) of croplands were sprayed at least once. This is an area equivalent to about one-seventh of South Vietnam.
The most commonly used herbicide was called agent orange, a one-to-one blend of two phenoxy herbicides, 2, 4-D and 2, 4, 5-T. Picloram and cacodylic acid were also used, but in much smaller amounts. In total, this military action used about 25, 000 tons of 2, 4-D; 21, 000 tons of 2, 4, 5-T; and 1, 500 tons of picloram. Agent orange was sprayed at a rate of about 22.3 lb/acre (25 kg/ha), equivalent to about ten times the rate at which those same chemicals were used for plant control in forestry. The spray rate was much more intense during warfare, because the intention was to destroy the ecosystems through ecocide, rather than to manage them towards a more positive purpose.
The ecological damage caused by the military use of herbicides in Vietnam was not studied in detail; however, cursory surveys were made by some visiting ecologists. These scientists observed that coastal man-grove forests were especially sensitive to herbicides. About 36% of the mangrove ecosystem of South Vietnam was subjected to herbicides, amounting to 272, 000 acres (110, 000 ha). Almost all of the plant species of mangrove forests proved to be highly vulnerable to herbicides, including the dominant species, the red mangrove. Consequently, mangrove forests were devastated over large areas, and extensive coastal barrens were created.
There were also severe ecological effects of herbicide spraying in the extremely biodiverse upland forests of Vietnam, especially rain forests. Mature tropical forests in this region have many species of hardwood trees. Because this forested ecosystem has such a dense and complexly layered canopy, a single spraying of herbicide killed only about 10% of the larger trees. Resprays of upland forests were often made, however, to achieve a greater and longer-lasting defoliation. To achieve this effect, about 34% of the area of Vietnam that was subjected to herbicides was treated more than once.
The effects on animals of the herbicide spraying in Vietnam were not well documented; however, there are many accounts of sparse populations of birds, mammals, reptiles, and other animals in the herbicide-treated mangrove forests and of large decreases in the yield of near-shore fisheries, for which an intact mangrove ecosystem provides important spawning and nursery habitat. More than a decade after the war, Vietnamese ecologists examined an inland valley that had been converted by herbicide spraying from a rich upland tropical forest into a degraded ecosystem dominated by grasses and shrubs. The secondary, degraded landscape only supported 24 species of birds and five species of mammals, compared with 145-170 birds and 30-55 mammals in nearby unsprayed forests.
The effects on wild animals were probably caused mostly by habitat changes resulting from herbicide spraying. There were also numerous reports of domesticated agricultural animals becoming ill or dying. Because of the constraints of warfare, the specific causes of these illnesses and deaths were never studied properly by veterinary scientists; however, these ailments were commonly attributed to toxic effects of exposure to herbicides, mostly ingested with their food.
Use of petroleum as a weapon during the Gulf War of 1991-1992
Large quantities of petroleum are often spilled at sea during warfare, mostly through the shelling of tankers or facilities such as offshore production platforms. During the Iran-Iraq War of the 1980s and the brief Gulf War of 1991-1992, oil spills were deliberately used to gain tactical advantage, as well as to inflict economic damages on the postwar economy.
The world’s all-time largest oceanic spill of petroleum occurred during the Gulf War, when the Iraqi military deliberately released almost 1.0 million tons (907, 441 tonnes) of crude oil into the Persian Gulf from several tankers and an offshore facility for loading tankers. In part, the oil was spilled to establish a defensive barrier against an amphibious counter-invasion of Kuwait by coalition forces. Presumably, if the immense quantities of spilled petroleum could have been ignited, the floating inferno might have provided an effective barrier to a seaborne invasion. The spilled oil might also have created some military advantage by contaminating the seawater intakes of Saudi Arabian desalination plants, which supply most of that nation’s fresh water and, therefore, have great strategic value.
Another view is that this immense spillage of petroleum into the ocean was simply intended to wreak economic and ecological havoc. Certainly, there was no other reason for the even larger spillages that were deliberately caused when Iraqi forces sabotaged and ignited the wellheads of 788 Kuwaiti oil wells on land. This act caused enormous releases of petroleum and combustion residues to the land and air for the following year. Although the wells were capped, there will be lingering pollution of the land for many decades.
Controls over the use of chemical weapons
The first treaty to control the use of chemical weapons was the Geneva Protocol, which was negotiated in 1925 and subsequently signed by the representatives of 132 nations. The Geneva Protocol was stimulated by the horrific uses of chemical weapons during World War I. It banned the use of asphyxiating, poisonous, or other gases, as well as bacteriological methods of warfare. In spite of signing this treaty, it is well known that all major nations subsequently engaged in research towards the development of new, more effective chemical and bacteriological weapons.
In 1993, negotiators for various nations finalized the Chemical Weapons Convention, which would require the destruction of all chemical weapons within 10-15 years of the ratification of the treaty. This treaty has been signed by 147 nations, but it is not yet being enforced. The Chemical Weapons Convention is an actual pact to achieve a disarmament of chemical weapons; however, its effectiveness depends on its ratification by all countries having significant stockpiles of chemical weapons, their subsequent good faith actions in executing the provisions of the treaty, and
KEY TERMS
Defoliant— A chemical that kills the leaves of plants and causes them to fall off.
Ecocide— The deliberate carrying out of anti-environmental actions over a large area as a tactical element of a military strategy.
Harassing agent— A chemical which causes temporary incapacitation of animals, including humans.
Herbicide— A chemical that kills entire plants; herbicide action can be selective.
Nerve agent— A chemical that kills animals, including humans, by attacking the nervous system and inhibiting vital functions such as respiration and heartbeat.
the effectiveness of the associated international monitoring program to detect non-compliance.
Terrorism and chemical weapons
Chemicals in the hands of terrorists hold a grave potential for disaster; indeed, chemical, nuclear, and biological weapons have been dubbed “weapons of mass destruction.” In 1995, the Japanese sect called Aum Shinrikyo unleashed sarin gas in a Tokyo subway. Twelve people died, and 5, 000 were sickened from the attack; experts claim that the toll should have been higher but for the terrorists’ minor errors. Counterterrorism forces have been established by various Federal agencies, but the substances and handbooks for synthesizing chemicals are available on the Internet, through the mail, and at survivalist shows. Dangers of dispersing chemicals (including effects of the weather) may dissuade some, but there are unknown quantities, such as who might have a grudge and the knowledge to choose chemicals as weapons. In addition, the location and speed of a chemical attack might make nuclear weapons seem better controlled and less dangerous by comparison.
Resources
BOOKS
Charles, Daniel. Master Mind: The Rise and Fall of Fritz Haber, the Nobel Laureate Who Launched the Age of Chemical Warfare. New York: Ecco, 2005.
Coleman, Kim. A History of Chemical Warfare. New York: Palgrave MacMillan, 2005.
Tucker, Jonathan. War of Nerves: Chemical Warfare from World War I to al-Qaeda. New York: Pantheon, 2006.
PERIODICALS
“Better Killing Through Chemistry.” Scientific American. (December 2001).
Byrne, W. Russell, et al., “Clinical Recognition and Management of Patients Exposed to Biological Warfare Agents,” Laboratory Aspects of Biowarfare (Clinics in Laboratory Medicine) 21, No. 3, (September 2001): 459.
Dire, D. J., and T. W. McGovern. “CBRNE—Biological Warfare Agents.” eMedicine Journal no. 4 (April 2002): 1-39.
OTHER
“US Knew of Bioterror Tests in Iraq.” BBC News. August 20, 2002.
Bill Freedman
Chris Cavette
Chemical Warfare
Chemical warfare
Chemical warfare involves the use of natural or synthetic substances to incapacitate or kill an enemy or to deny them the use of resources such as agricultural products or screening foliage. The effects of the chemicals may last only a short time, or they may result in permanent damage and death. Most of the chemicals used are known to be toxic to humans or plant life. Other normally benign (mild) chemicals have also been intentionally misused in more broadly destructive anti-environmental actions, called ecocide, and as a crude method of causing mayhem and damaging an enemy's economic system. The deliberate dumping of large quantities of crude oil on the land or in the ocean is an example.
Chemical warfare dates back to the earliest use of weapons. Poisoned arrows and darts used for hunting were also used as weapons in intertribal conflicts (and primitive peoples still use them for these purposes today). In 431 b.c., the Spartans used burning sulfur and pitch to produce clouds of suffocating sulfur dioxide in their sieges against Athenian cities. When the Romans defeated the Carthaginians of North Africa in 146 b.c. during the last of a series of Punic Wars, they levelled the city of Carthage and treated the surrounding fields with salt to destroy the agricultural capability of the land, thereby preventing the rebuilding of the city.
The attraction of chemicals as agents of warfare was their ability to inflict mass casualties or damage to an enemy with only limited risk to the forces using the chemicals. Poisoning a town's water supply, for example, posed almost no threat to an attacking army, yet resulted in the death of thousands of the town's defenders. In many cases, the chemicals were also not detectable by the enemy until it was too late to take action.
Chemical agents can be classified into several general categories. Of those that attack humans, some, like tear gas, cause only temporary incapacitation. Other agents cause violent skin irritation and blistering, and may result in death. Some agents are poisonous and are absorbed into the bloodstream through the lungs or skin to kill the victim. Nerve agents attack the nervous system and kill by causing the body's vital functions to cease. Still others cause psychological reactions including disorientation and hallucinations. Chemical agents which attack vegetation include defoliants that kill plant leaves, herbicides that kill the entire plant, and soil sterilants that prevent the growth of new vegetation.
Antipersonnel agents—chemicals used against people
The first large-scale use of poisonous chemicals in warfare occurred during World War I. More than 100,000 tons (90,700 metric tons) of lethal chemicals were used by both sides during several battles in an effort to break the stalemate of endless trench warfare. The most commonly used chemicals were four lung-destroying poisons: chlorine, chloropicrin, phosgene, and trichloromethyl chloroformate, along with a skin-blistering agent known as mustard gas , or bis (2-chloroethyl) sulfide. These poisons caused about 100,000 deaths and another 1.2 million injuries, almost all of which involved military personnel.
Despite the agreements of the Geneva Protocol of 1925 to ban the use of most chemical weapons, the United States, Britain, Japan, Germany, Russia and other countries all continued development of these weapons during the period between World War I and World War
II. This development included experimentation on animals and humans. Although there was only limited use of chemical weapons during World War II, the opposing sides had large stockpiles ready to deploy against military and civilian targets.
During the war in Vietnam, the United States military used a nonlethal "harassing agent" during many operations. About 9,000 tons (8,167 tonnes) of tear gas, known as CS or o-chlorobenzolmalononitrile, were sprayed over 2.5 million acres (1.0 million ha) of South Vietnam, rendering the areas uninhabitable for 15-45 days. Although CS is classified as nonlethal, several hundred deaths have been reported in cases when CS has been used in heavy concentrations in confined spaces such as underground bunkers and bomb shelters.
Poisonous chemicals were also used during the Iran-Iraq War of 1981-1987, especially by Iraqi forces. During that war, both soldiers and civilians were targets of chemical weapons. Perhaps the most famous incident was the gassing of Halabja, a town in northern Iraq that had been overrun by Iranian-supported Kurds. The Iraqi military attacked Halabja with two rapidly acting neurotoxins, known as sabin and tabun, which cause rapid death by interfering with the transmission of nerve impulses. About 5,000 people, mostly civilians, were killed in this incident.
Use of herbicides during the Vietnam War
During the Vietnam War, the U.S. military used large quantities of herbicides to deny their enemies agricultural food production and forest cover. Between 1961 and 1971, about 3.2 million acres (1.3 million ha) of forest and 247,000 acres (100,000 ha) of croplands were sprayed at least once. This is an area equivalent to about one-seventh of South Vietnam.
The most commonly used herbicide was called agent orange , a one-to-one blend of two phenoxy herbicides,
2,4-D and 2,4,5-T. Picloram and cacodylic acid were also used, but in much smaller amounts. In total, this military action used about 25,000 tons of 2,4-D; 21,000 tons of 2,4,5-T; and 1,500 tons of picloram. Agent orange was sprayed at a rate of about 22.3 lb/acre (25 kg/ha), equivalent to about ten times the rate at which those same chemicals were used for plant control in forestry . The spray rate was much more intense during warfare, because the intention was to destroy the ecosystems through ecocide, rather than to manage them towards a more positive purpose.
The ecological damages caused by the military use of herbicides in Vietnam were not studied in detail; however, cursory surveys were made by some visiting ecologists. These scientists observed that coastal mangrove forests were especially sensitive to herbicides. About 36% of the mangrove ecosystem of South Vietnam was subjected to herbicides, amounting to 272,000 acres (110,000 ha). Almost all of the plant species of mangrove forests proved to be highly vulnerable to herbicides, including the dominant species, the red mangrove. Consequently, mangrove forests were devastated over large areas, and extensive coastal barrens were created.
There were also severe ecological effects of herbicide spraying in the extremely biodiverse upland forests of Vietnam, especially rain forests. Mature tropical forests in this region have many species of hardwood trees. Because this forested ecosystem has such a dense and complexly layered canopy, a single spraying of herbicide killed only about 10% of the larger trees. Resprays of upland forests were often made, however, to achieve a greater and longer-lasting defoliation. To achieve this effect, about 34% of the area of Vietnam that was subjected to herbicides was treated more than once.
The effects on animals of the herbicide spraying in Vietnam were not well documented; however, there are many accounts of sparse populations of birds , mammals , reptiles , and other animals in the herbicide-treated mangrove forests and of large decreases in the yield of near-shore fisheries, for which an intact mangrove ecosystem provides important spawning and nursery habitat . More than a decade after the war, Vietnamese ecologists examined an inland valley that had been converted by herbicide spraying from a rich upland tropical forest into a degraded ecosystem dominated by grasses and shrubs. The secondary, degraded landscape only supported 24 species of birds and five species of mammals, compared with 145-170 birds and 30-55 mammals in nearby unsprayed forests.
The effects on wild animals were probably caused mostly by habitat changes resulting from herbicide spraying. There were also numerous reports of domesticated agricultural animals becoming ill or dying. Because of the constraints of warfare, the specific causes of these illnesses and deaths were never studied properly by veterinary scientists; however, these ailments were commonly attributed to toxic effects of exposure to herbicides, mostly ingested with their food.
Use of petroleum as a weapon during the Gulf War
Large quantities of petroleum are often spilled at sea during warfare, mostly through the shelling of tankers or facilities such as offshore production platforms. During the Iran-Iraq War of the 1980s and the brief Gulf War of 1991-1992, oil spills were deliberately used to gain tactical advantage, as well as inflicting economic damages on the postwar economy.
The world's all-time largest oceanic spill of petroleum occurred during the Gulf War, when the Iraqi military deliberately released almost 1.0 million tons (907,441 tonnes) of crude oil into the Persian Gulf from several tankers and an offshore facility for loading tankers. In part, the oil was spilled to establish a defensive barrier against an amphibious counter-invasion of Kuwait by coalition forces. Presumably, if the immense quantities of spilled petroleum could have been ignited, the floating inferno might have provided an effective barrier to a seaborne invasion. The spilled oil might also have created some military advantage by contaminating the seawater intakes of Saudi Arabian desalination plants, which supply most of that nation's fresh water and, therefore, have great strategic value.
Another view is that this immense spillage of petroleum into the ocean was simply intended to wreak economic and ecological havoc. Certainly, there was no other reason for the even larger spillages that were deliberately caused when Iraqi forces sabotaged and ignited the wellheads of 788 Kuwaiti oil wells on land. This act caused enormous releases of petroleum and combustion residues to the land and air for the following year. Although the wells were capped, there will be lingering pollution of the land for many decades.
Controls over the use of chemical weapons
The first treaty to control the use of chemical weapons was negotiated in 1925 and subsequently signed by the representatives of 132 nations. This Geneva Protocol was stimulated by the horrific uses of chemical weapons during World War I, and it banned the use of asphyxiating, poisonous, or other gases, as well as bacteriological methods of warfare. In spite of their having signed this treaty, it is well known that all major nations subsequently engaged in research towards the development of new, more effective chemical and bacteriological weapons.
In 1993, negotiators for various nations finalized the Chemical Weapons Convention, which would require the destruction of all chemical weapons within 10–15 years of the ratification of the treaty. This treaty has been signed by 147 nations but is not yet being enforced. The Chemical Weapons Convention is an actual pact to achieve a disarmament of chemical weapons; however, its effectiveness depends on its ratification by all countries having significant stockpiles of chemical weapons, their subsequent good faith actions in executing the provisions of the treaty, and the effectiveness of the associated international monitoring program to detect non-compliance.
It is important to understand that the destruction of existing chemical weapons will not be an inexpensive activity. It has been estimated that it could cost $16–20 billion just to safely destroy the chemical weapons of the United States and Russia.
Terrorism and chemical weapons
Chemicals in the hands of terrorists hold a grave potential for disaster, according to experts in "weapons of mass destruction," which include chemical, biological, and nuclear (or radiological) devices. In 1995, the Japanese sect called Aum Shinrikyo unleashed sarin gas in a Tokyo subway. Twelve people died, and 5,000 got sick from the attack; and experts claim that the toll should have been higher but for the terrorists' minor errors. Counterterrorism forces have been established by various Federal agencies, but the substances and handbooks for synthesizing chemicals are available on the Internet, through the mail, and at survivalist shows. Dangers of dispersing chemicals (including effects of the weather ) may dissuade some; but the unknown quantities of who might have a grudge, the knowledge to choose chemicals as weapons, and the location and speed of a chemical attack make nuclear weapons seem better controlled and less dangerous by comparison.
See also Poisons and toxins.
Resources
books
Fleming, D. O., and D. L. Hunt. Biological Safety: Principles and Practices. 3rd ed. Washington: American Society for Microbiology, 2000.
Franz, David R., and Nancy K. Jaax. "Ricin Toxin." MedicalAspects of Chemical and Biological Warfare. Washington, DC: Borden Institute, Walter Reed Army Medical Center, 1997. p. 632.
Freedman, B. Environmental Ecology. 2nd ed. Academic Press, 1994.
Harris, Robert, and Jeremy Paxman. A Higher Form of Killing. Hill and Wang, 1982.
Proliferation: Threat and Response. Washington, DC: Department of Defense, 2001. p.15.
Sivard, R. L. World Military and Social Expenditures, 1993. World Priorities, 1993.
Tucker, Jonathan B., and Jason Pate. "The Minnesota Patriots Council." Toxic Terror: Assessing Terrorist Use of Chemical and Biological Weapons. Cambridge, MA: MIT Press, 2000. pp. 159-183.
periodicals
"Better Killing Through Chemistry." Scientific American (December 2001).
Byrne, W. Russell, et al."Clinical Recognition and Management of Patients Exposed to Biological Warfare Agents," Laboratory Aspects of Biowarfare (Clinics in Laboratory Medicine) 21, no. 3, (September 2001): 459.
Dire, D. J., and T. W. McGovern. "CBRNE—Biological Warfare Agents." eMedicine Journal no. 4 (April 2002): 1-39.
Dutton, Gail. "Biotechnology Counters Bioterrorism." GeneticEngineering News no. 21 (December 2000): 1-22ff.
Dyer, G. "Environmental Warfare in the Gulf." Ecodecision (1991): 21-31.
Greenfield, Ronald A. "Microbiological, Biological, and Chemical Weapons of Warfare And Terrorism." American Journal of The Medical Sciences 323 no. 6 (2002): 326-340.
Reutter, S. "Hazards of Chemical Weapons Release During War: New Perspectives." Environmental Health Perspectives 107, no. 12 (1999): 985-990.
other
"US Knew of Bioterror Tests in Iraq." BBC News. August 20, 2002.
Bill Freedman
Chris Cavette
KEY TERMS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- Defoliant
—A chemical that kills the leaves of plants and causes them to fall off.
- Ecocide
—The deliberate carrying out of antienvironmental actions over a large area as a tactical element of a military strategy.
- Harassing agent
—A chemical which causes temporary incapacitation of animals, including humans.
- Herbicide
—A chemical that kills entire plants, often selectively.
- Nerve agent
—A chemical which kills animals, including humans, by attacking the nervous system and causing vital functions, such as respiration and heartbeat, to cease.
Chemical Warfare
Chemical warfare
Chemical warfare involves the use of natural or synthetic (human-made) substances to disable or kill an enemy or to deny them the use of resources such as agricultural products or foliage in which to hide. The effects of the chemicals may last only a short time, or they may result in permanent damage and death. Most of the chemicals used are known to be toxic (poisonous) to humans or plant life. In some cases, normally harmless chemicals have also been used to damage an enemy's environment. Such actions have been called ecocide and are one method for disrupting an enemy's economic system. The deliberate dumping of large quantities of crude oil on the land or in the ocean is an example of ecocide.
The appeal of chemicals as agents of warfare is their ability to cause mass casualties or damage to an enemy with only limited risk to the forces using the chemicals. Poisoning a town's water supply, for example, poses almost no threat to an attacking army. Yet the action could result in the death of thousands of the town's defenders. In many cases, chemicals are not detectable by the enemy until it is too late for them to take action.
History
Chemical warfare dates back to the earliest use of weapons. Poisoned arrows and darts used for hunting by primitive peoples have also been used as weapons in battles between tribal groups. In 431 b.c., the Spartans used burning sulfur and pitch to produce clouds of suffocating sulfur dioxide in their sieges against Athenian cities. When the Romans defeated the Carthaginians of North Africa in 146 b.c., they destroyed the city of Carthage and spread salt on surrounding fields to destroy the agricultural capability of the land. The Romans' intent was to prevent the Carthaginians from rebuilding their city.
Types of chemical agents
Chemical agents can be classified into several general categories, ranging from those that cause relatively little harm to those that can cause death. One group includes those that produce only temporary damage. As an example, tear gas tends to cause coughing, sneezing, and general respiratory discomfort, but this discomfort passes within a relatively short period of time.
Other agents cause violent skin irritation and blistering and may result in death. Still other agents are poisonous and are absorbed into the victim's bloodstream through the lungs or skin, causing death. Nerve agents attack the nervous system and kill by causing the body's vital functions (respiration, circulation, etc.) to cease. Finally, other agents cause psychological reactions including disorientation and hallucinations.
Words to Know
Defoliant: A chemical that kills the leaves of plants and causes them to fall off.
Ecocide: Deliberate attempts to destroy or damage the environment over a large area as a tactical element of a military strategy.
Harassing agent: A chemical that causes temporary damage to animals, including humans.
Herbicide: A chemical that kills entire plants, often selectively.
Nerve agent: A chemical that kills animals, including humans, by attacking the nervous system and causing the disruption of vital functions such as respiration and heartbeat.
Another group of chemical agents include those that attack vegetation, damaging or killing plants. Some examples include defoliants that kill a plant's leaves, herbicides that kill the entire plant, and soil sterilants that prevent the growth of new vegetation.
Antipersonnel agents: chemicals used against people. The first large-scale use of poisonous chemicals in warfare occurred during World War I (1914–18). More than 100,000 tons (90,000 metric tons) of lethal chemicals were used by both sides in an effort to break the stalemate of endless trench warfare. The most commonly used chemicals were four lung-destroying poisons: chlorine, chloropicrin, phosgene, and trichloromethyl chloroformate, along with a skin-blistering agent known as mustard gas, or bis(2-chloroethyl) sulfide. These poisons caused about 100,000 deaths and another 1.2 million injuries, almost all of which involved military personnel.
In 1925, many of the world's nations signed an agreement, called the Geneva Protocol, to discontinue production of chemical agents for military use. Despite this agreement, the United States, Britain, Japan,
Germany, Russia, and other countries all continued development of these weapons during the period between World War I and World War II (the 1920s and most of the 1930s). This research included experimentation on animals and humans. Although chemical weapons were not used very widely during World War II (1939–45), the opposing sides had large stockpiles ready to deploy against military and civilian targets.
During the civil war in Vietnam, the U.S. military used a "harassing agent" during many of its operations. (The United States sided with and supplied the South Vietnamese in the early 1960s and joined their military efforts against the North in 1964.) The agent was a tear gas known as CS or o-chlorobenzolmalononitrile. CS was not regarded as toxic to humans and was intended only to make an area uninhabitable for 15 to 45 days. A total of about 9,000 tons (8,000 metric tons) of CS were sprayed over 2.5 million acres (1.0 million hectares) of South Vietnam. Although CS was classified as nonlethal (not deadly), several hundred deaths were later reported when the gas was used in heavy concentrations in confined spaces such as underground bunkers and bomb shelters.
Poisonous chemicals were also used during the Iran-Iraq War of 1981–87, especially by Iraqi forces. During that war, both soldiers and civilians were targets of chemical weapons. Perhaps the most famous incident was the gassing of Halabja, a town in northern Iraq that had been overrun by Iranian-supported Kurds. The Iraqi military attacked Halabja with two fast-acting neurotoxins, sarin and tabun. Sarin and tabun cause rapid death by interfering with the transmission of nerve impulses. Muscular spasms develop and a person dies when he or she is no longer able to breathe. About 5,000 people, mostly civilians, were killed in this incident.
Use of herbicides during the Vietnam War. Herbicides are chemicals that were originally developed to kill weeds. However, they are just as effective at killing agricultural crops as they are at killing weeds. During the Vietnam War, in addition to tear gas, the U.S. military relied heavily on the use of herbicides as a weapon of war. The purpose of using herbicides was two fold: first, to destroy enemy crops and disrupt their food supply, and second, to remove forest cover in which enemy troops might hide. Between 1961 and 1971, about 3.2 million acres (1.3 million hectares) of forest and 247,000 acres (100,000 hectares) of Vietnamese croplands were sprayed at least once. This area is equivalent to about one-seventh of the total land area of South Vietnam.
The most commonly used herbicide was called Agent Orange, a blend of two herbicides known as 2,4-D and 2,4,5-T. Two other herbicides, picloram and cacodylic acid, were also used, but in much smaller amounts. In total, about 25,000 tons of 2,4-D, 21,000 tons of 2,4,5-T, and 1,500 tons of picloram were utilized as a result of U.S. military actions during the war.
In particular, Agent Orange was sprayed at a rate of about 22.3 pounds per acre (25 kilograms per hectare). This rate is equivalent to about 10 times the rate at which those same chemicals are used for plant control purposes in forestry. The higher spray rate was used in Vietnam because the intention of the U.S. military was the ultimate destruction of Vietnamese ecosystems (its communities of plants and animals).
The ecological damages caused by the military use of herbicides in Vietnam were not studied in detail. However, a few casual surveys have been made by some visiting ecologists. These scientists observed that coastal mangrove forests (tropical trees and shrubs that form dense greenery) were especially sensitive to treatment with herbicides. About 36 percent of the mangrove ecosystem of South Vietnam was sprayed with
herbicides, a total of about 272,000 acres (110,000 hectares). Almost all of the plant species of mangrove forests proved to be highly vulnerable to herbicides, including the dominant species of tree, red mangrove.
Severe ecological effects of herbicide spraying were also observed in the biodiverse upland forests of Vietnam, especially its rain forests. Mature tropical forests in this region have many species of hardwood trees. These forests are covered by a dense canopy consisting of complex layers. As a result, a single spraying of herbicide typically kills only about 10 percent of the larger trees. However, the goal of the U.S. military was to achieve a more extensive and longer-lasting defoliation. Hence, they sprayed many areas more than once. In fact, about 34 percent of Vietnam was treated with herbicides more than once.
The effects on animals of herbicide spraying in Vietnam are not well documented. However, there are many accounts of reduced populations of birds, mammals, reptiles, and other animals in the mangrove forests treated with herbicides. In addition, large decreases in the yield of nearshore fisheries have been attributed to the spraying of mangrove ecosystems, which provide spawning and nursery habitat for the fish.
The effects on wild animals were probably caused mostly by habitat changes resulting from herbicide spraying. However, there have also been numerous reports of domesticated agricultural animals becoming ill or dying. Because of the constraints of warfare, the specific causes of these illnesses and deaths were never studied properly by veterinary scientists. However, these ailments were commonly attributed to toxic effects of exposure to herbicides, mostly ingested by the animals with their food.
Use of petroleum as a weapon during the Persian Gulf War. Large quantities of petroleum are often spilled at sea during warfare, mostly as the result of damage to oil tankers or other facilities such as offshore production platforms. During the Iran-Iraq War of the 1980s and the Persian Gulf War of 1991–92, however, oil spills were deliberately used to gain military advantage, as well as to inflict economic damages on the enemy's postwar economy.
The world's all-time largest oceanic spill of petroleum occurred during the Persian Gulf War. The Iraqi military deliberately released almost 1 million tons (900,000 metric tons) of crude oil into the Persian Gulf from several tankers and an offshore facility for loading tankers. In part, the oil was spilled to establish a defensive barrier against an expected attack by the anti-Iraqi coalition forces. The hope was that igniting the immense quantities of spilled petroleum would create a floating inferno that would provide an effective barrier against a seaborne invasion. It is believed that the Iraqis also sought to contaminate the seawater used in desalination plants (salt removal facilities) that supply most of Saudi Arabia with freshwater.
Controls over the use of chemical weapons
The first treaty to control the use of chemical weapons was the Geneva Protocol, agreed upon in 1925 and subsequently signed by 132 nations. This treaty was prompted by the horrible uses of chemical weapons during World War I. It banned the use of asphyxiating (suffocating), poisonous, or other gases, as well as bacteriological (germ) methods of warfare. In spite of having signed this treaty, however, all major nations are known to have continued research on new and more effective chemical and bacteriological weapons.
In 1993, negotiators for various nations met at a Chemical Weapons Convention and agreed to the destruction of all chemical weapons within a 10 to 15 year period following ratification of a chemical weapons treaty. By the end of 2000, 174 nations had signed, ratified, or acceded to the treaty. In the long run, its effectiveness depends upon its ratification by all countries having significant stockpiles of chemical weapons, the countries' commitment to following the terms of the treaty, and the power of an international monitoring program to expose and discipline member countries ignoring the treaty.
Part of the problem in obtaining an effective chemical weapons treaty is desire. Nations have to want to destroy their stockpiles of weapons and discontinue making more of them. Another part of the problem is cost. By one estimate, it will cost $16 to $20 billion just to safely destroy the chemical weapons of the world's two largest military powers, the United States and Russia.
[See also Agent Orange; Agrochemicals; Poisons and toxins ]
Chemical Warfare
Chemical Warfare
█ BRIAN HOYLE
Chemical warfare involves the aggressive use of bulk chemicals that cause death or grave injury. These chemicals are different from the lethal chemical compounds that are part of infectious bacteria or viruses. The latter constitute biological warfare.
History of Chemical Warfare
The use of chemicals in warfare began centuries ago, when early combatants learned that smoke from burning sulfur caused discomfort when it drifted into enemy fortifications. The dawn of modern chemical warfare occurred during World War I. On April 15, 1915, German forces released about 160 tons of chlorine gas into the wind near the Belgian village of Ypres. The clouds of the gas drifted into Allied forces, killing some 5,000 soldiers. Two days later, another chlorine attack at the same village killed 5,000 more soldiers.
During the remainder of World War I, German and British forces used chlorine gas, and other chemicals (i.e., mustard gas and phosphene) with increasing tendency. Estimates are that approximately 113,000 tons of chemical weapons were used from 1915 to 1918, killing some 92,000 people and injuring over one million people.
The aerial release of chemicals brought unpredictable results at the mercy of prevailing winds. Shifting winds could send the deadly cloud back to the attacking troops. Later during World War I, more sophisticated use of chemical weapons began. For example, the French used shells filled with an irritant to the eyes, skin, and lining of the nose and lungs, and the Germans fired lead balls coated with similar irritant.
The horrors of chemical warfare during World War I prompted the drafting of the Geneva Protocol of 1925, which banned chemical and biological weapons of warfare. The protocol was initially signed by 38 nations (now over 130 nations). As history has shown, the protocol has
not stopped the use of such weapons by rouge states or fringe elements in order to commit terrorism.
Aerial releases of lethal chemicals did not occur in World War II. However, the Germans developed a new class of chemical weapon called nerve agents. During the 1930s and 1940s, agents such as Tabun, Sarin, and Soman were created.
Chemical warfare research continued during the Cold War tensions during the 1950s. During this time, military chemists in the United Kingdom and then in the United States adapted insecticides to produce the most lethal chemical agent then known. The agent was code named VX. The potency of VX was accidentally demonstrated in 1968, when a testing accident at the VX manufacturing plant in Dugway, Utah killed over 6,000 sheep.
During the Vietnam War of the 1970s, the U.S. use of defoliants—chemicals that killed vegetation, permitting a clearer detection of the enemy—was extensive. One of these compounds, Agent Orange, has become infamous as the alleged cause of a variety of physical ailments in veterans of the conflict.
In the last few decades, chemicals have become the tools of terrorists. A particularly well-known example is the release of Sarin gas into the Tokyo subway system by the religious cult Aum Shinrikyo in March of 1995. The gas killed 12 people and injured over 5,500 people in 16 stations.
Chemical Warfare Agents
There are several classes of chemical warfare agents, based on their effects:
- compounds that cause choking or that irritate the lungs,
- blister agents (also called vesicants),
- blood agents,
- nerve agents,
- herbicides, and
- incendiaries
Choking and irritant agents. There are a number of compounds that cause choking or irritation of lung tissue. Examples include chlorine, phosgene (carbonyl chloride), diphosgene, chloropicrin, ethyldichloroarsine, and perflurorisobutylene.
Chlorine gas is suffocating and quickly burns tissues in the nose, mouth, and lungs. The burned tissue can die and slough off, causing lasting damage. Chlorine gas dissipates in the air very quickly. If exposure is not too long, than damage can be minor. In contrast, the compound called disphosgene is a liquid at room temperature, and so persists much longer.
Blister agents. As their name implies, blister agents cause the formation of large and painful blisters on the skin. Eye and lung tissue can also be damaged. A well-known example of a blistering agent dating from World War I is mustard gas. The damage to cells of the skin cause blistering up to 24 hours after exposure to mustard gas. These blisters take a long time to heal and can send the body into a lethal shock reaction.
Other examples of blistering agents include nitrogen mustard, lewisite, and phenyldichloroarsine. The latter compound is a liquid, which can be sprayed onto an enemy or released from a balloon, helicopter, or airplane.
Blood agents. These compounds interfere with the body's ability to transport oxygen in the bloodstream. This is done by either blocking the use of oxygen by cells in the body or by blocking the ability of the blood to take up the oxygen. Examples include hydrogen cyanide (also called prussic acid), cyanogen chloride, arsine, carbon monoxide, and hydrogen sulfide.
Hydrogen cyanide is initially a liquid at room temperature, but it quickly evaporates. This compound is noteworthy in recent world history, as it was used by Iraq in 1988 on an attack on the Kurdish town of Halabja during the Iran-Iraq war. Because of its past use by Iraq, hydrogen cyanide was one of the major concerns of United Nations inspectors who inspected various facilities in Iraq during the winter of 2003.
Compounds such as arsine and carbon monoxide destroy the ability of the hemoglobin component of the blood to bind oxygen. Arsine does this by destroying the red blood cells. Carbon monoxide binds to hemoglobin, blocking the binding of oxygen.
Nerve agents. Compounds that are classified as nerve agents interfere with the body's transmission of nerve impulses. This is done by disrupting the activity of a chemical called acetyl cholinesterase, which functions to bridge the gap between adjacent nerve cells, permitting an electrical nerve signal to pass from one nerve cell to the next.
Nerve agents were first developed in 1936, following the development of organophosphate types of pesticides. The first nerve agent that was made is called Tabrun. It is a member of what is known as the G series of nerve agents. Other G series members are Sarin and Soman. Sarin is particularly lethal; a small amount absorbed through the skin can kill a man within two minutes. When inhaled, death occurs within 15 minutes. Sarin is infamous as the gas released into the Tokyo subway system by the fringe group Aum Shinrikyo in 1995.
Another series of nerve agents are called the V series. Members of this series—which are commonly abbreviated according to their chemical composition—are more potent than the agents of the G series. As well, they persist longer in the environment. They can, for example, be applied to surfaces like roads as a slime.
Examples of V series agents include VX, VE, VG, and VM. VX is extremely potent; a drop of the liquid absorbed through the skin is lethal within a few hours without treatment.
Nerve agents can be contained in missiles or in canisters for lengthy time periods. Examination of caves in Afghanistan that were used as strongholds by the terrorist group al Qaeda has revealed evidence of stores of Sarin and VX.
Herbicides. Herbicides are chemicals that kill vegetation. Such chemicals are often used in everyday life to keep lawns free of weeds (although more environmentallyfriendly alternatives are becoming popular). When used in war, herbicides are weapons of mass destruction to foliage. Destruction of plants and the resulting loss of leaf cover remove much of the concealment for an enemy in a forested area. These philosophies led to the massive use of Agent Orange by the United States in the Vietnam War in the 1970s. Since that war, the damaging effects of herbicides like Agent Orange and paraquat on the human nervous and immune systems has become evident.
Incendiaries. Incendiaries are chemicals that cause fires. In warfare, they are also to remove vegetation. An infamous incendiary is napalm. Napalm is a mixture of naphthenic acid, coconut fatty acids, and palm oil. In addition to its highly flammable property, napalm absorbs into exposed skin, where it can cause severe burns if ignited. Napalm was used as an offensive weapon by the United States during the Vietnam War.
Modern Day Chemical Warfare
In 2003, the use of chemical weapons remains a threat from rogue states and terrorists. Current world attention is focused on the former chemical warfare capabilities of Iraq. It is known that Iraq engaged in chemical warfare research and weaponization in the 1980s and 1990s, and as of early 2003, before the U.S. war in Iraq, had not fully complied with United Nations resolutions requiring disclosure and destruction of their chemical weapons program.
█ FURTHER READING:
BOOKS:
Ellison, D. Hank. Handbook of Chemical and Biological Warfare Agents. Boca Raton: CRC Press, 1999.
Harris, Robert, and Jeremy Paxman. A Higher Form of Killing: The Secret History of Chemical and Biological Warfare. New York: Random House, 2002.
PERIODICALS:
Macintrye, A. G., C. G. W. Eitzen, Jr., R. Gum, et al. "Weapons of Mass Destruction Events with Contaminated Casualties: Effective Planning for Health Care Facilities." Journal of the American Medical Association no. 283 (2000): 252–253.
Munro, N.B., S.S. Talmage, G.D. Griffin, et al. "The Sources, Fate, and Toxicity of Chemical Warfare Agent Degradation Products." Environmental Health Perspectives no. 107 (1999): 933–974.
Nakajima, T., S. Ohta, Y. Fukushima, et al. "Sequelae of Sarin Toxicity at One and Three Years after Exposure in Matsumoto, Japan." Journal of Epidemiology no. 9 (1999): 337–343.
ELECTRONIC:
How Stuff Works. "How Biological and Chemical Warfare Works." 2002. <http://www.howstuffworks.com/Biochem-war.htm>(10 January 2003).
SEE ALSO
Chemical and Biological Detection Technologies
USAMRICD (United States Army Medical Research Institute of Chemical Defense)
chemical warfare
Fitting the clumsy helmets just in time,
But someone still was yelling out and stumbling
And flound'ring like a man in fire or lime…
Chemical warfare has evolved since then: from the asphyxiating chlorine; through the irritant, skin penetrating and bone marrow damaging mustard gas; to the acutely toxic skin-and inhalation-hazard nerve poisons — by-products of research on insecticidal organophosphate chemicals in the late 1930s. En route, and since, thousands of chemicals have been screened for their use in war, but the inventory of established chemical warfare agents remains at about twenty.
In parallel with the search for yet more effective agents, research has continued on antidotes and other means of protection. The modern infantryman has protective suits, gas masks, sensitive detectors, and injectable antidotes (but only to nerve poisons). Vehicles with air filtration units, and mobile hospitals with decontamination facilities, offer protection for other service units, the main objective being to avoid contact with the chemical agent.
Antidotes and hospitalization are no guarantees of a successful recovery following exposure to tabun, sarin, soman, or VX — nerve agents all, and capable at low concentrations of disrupting nerve transmission and the ability to breathe. Nerve agents can kill within minutes after inhalation, and in less than an hour following skin contact. For all chemical warfare agents the degree of injury and subsequent disability depends on the quantity of chemical inhaled or in contact with the skin.
Wilfred Owen captured the terror of chemical warfare, and his fumblers made up a sizeable proportion of the 1.3 million casualties it caused in World War I. Others fell victim because they had either no gas masks, or faulty masks, and latterly, inadequate skin protection when Germany introduced mustard gas in 1917. Some 27 000 servicemen died from the effects of chemical agents in World War I. This ratio of deaths to injuries, lower than with conventional munitions, led some to argue that chemical warfare was a more humane way of fighting.
Civilian casualties, caused by chemical agents being blown beyond the battlefields of northern France and Belgium border villages, numbered roughly 1000. Most civilians survived their ordeal, with some 110–120 deaths being recorded. Approximately 4000 factory workers in Britain, France, and the US were injured during the manufacture of chemical munitions between 1916–18. Iranian and Kurdish victims of Iraq's use of mustard gas and nerve agents in the 1980s were less fortunate. Tens of thousands, largely civilians, were injured, but a high percentage died, some 5000 in the Kurdish city of Halabja alone, according to estimates.
Unlike soldiers, civilians have relatively little protection against chemical warfare agents. The training provided to soldiers equips them, in part, for fighting in a chemical environment. Much of their training is to prevent any fumbling and to overcome the sense of isolation in their protective suits.
Remaining upwind, above ground level, and in a sealed room with an adequate air supply, will provide protection for civilians — if they have time to prepare. Iraq's Kurds had no warning, and the extensive casualties caused by chemical agents caused great panic and led to millions fleeing their homes to seek shelter in neighbouring countries.
The plight of the Kurds galvanized discussions on a chemical disarmament regime. Although most countries are signatories to the 1925 Geneva Protocol, which outlaws (first) use of chemical and biological warfare, this treaty does not forbid retaliation, nor does it have any policing powers. The 1993 Chemical Weapons Convention (CWC) remedies these deficiencies. Following ratification in the parliaments of 65 countries, the convention became international law in April 1997. Well over 120 countries have now ratified the Convention and agree to neither use, make, nor encourage others to produce chemical weapons. As proof of their good intentions all ratifiers have also agreed to inspection, at short notice, of any site, be it military base, chemical manufacturing plant, or area where agents may have been used. Adoption of the Convention requires countries such as the US, with some 30 000 tonnes of chemical agents, and Russia, with some 40 000 tonnes, to destroy all stocks within 10 years. The bill for Russia to comply with these provisions is an estimated $4 billion.
Details about stockpiles, sites, inventories of chemicals, and manufacturing locations are transmitted by governments to the Organisation for the Prohibition of Chemical Weapons (OPCW), based in the Hague. The OPCW oversees the CWC and organizes inspections.
Only two other countries, India and Iraq, are definitely known to have stocks of usable chemical munitions. India has ratified the Chemical Weapons Convention, Iraq has not. Following her defeat in the second Gulf War in 1991, Iraq has agreed to a United Nations Special Commission (UNSCOM) inspecting sites and destroying munitions and chemical and biological warfare manufacturing facilities. UNSCOM never completed this programme. Iraq expelled the UNSCOM team following bombing of the country by the US and the UK in 1999. Negotiations are continuing between Iraq and the UN about a new type of inspection regime.
A number of other countries, including Britain, France, and Italy, have declared that they possess some chemical warfare munitions, many of which were made before 1945. Small stocks of these munitions may be buried on disused military bases, and finding them will probably be more a chance event than the result of a specific investigation. In consequence, countries possessing stocks of these older, largely unusable munitions will have more than 10 years in which to destroy them.
Iraq brought chemical warfare up to date. The most extensive use, prior to this, of chemicals deliberately intended to injure or kill humans occurred between 1915–18. In the intervening years chemical agents have been used in other wars. Italy used mustard gas against Ethiopian forces in 1935–6. Japan is alleged to have used mustard gas against Chinese forces in 1938. In 1967, Britain claimed that an asphyxiating chemical agent had been used by Egypt against Yemeni troops.
Chemical warfare, however, is not only about lethal agents. Many countries adhere to the view that the use of chemical defoliants by the US in the Vietnam War both to remove the forest canopy and to destroy food crops was also chemical warfare. The US disagrees with this interpretation. Defoliants used in Vietnam caused a rapid leaf drop, increasing visibility in large swathes of inland and coastal forests. Destruction of forests and food crops caused considerable hardship in the locality. Regrettably, the concentrations of the chemicals used resulted in the loss of countless trees, and forests being replaced by grassland. The destruction is still evident today.
Riot control agents have also been used in warfare to force combatants to leave entrenched positions, exposing them to enemy fire. Use of riot-control agents in this context also constitutes chemical warfare. The CWC acknowledges this, and the use of riot control agents in war is now forbidden.
A disarmament treaty to prevent chemical warfare is now in place. Negotiations to secure it have taken almost 20 years. More countries are expected to ratify the CWC. Persuading all nations to do so and to follow the new rules is the ultimate goal.
Alastair Hay
See also poisons; war and the body.
Chemical Warfare
Chemical Warfare
Chemical warfare involves the aggressive use of bulk chemicals that cause death or grave injury. These chemicals are different from the lethal chemical compounds that are part of infectious bacteria or viruses. The latter constitute biological warfare.
Forensic examinations are a part of chemical warfare, especially when the nature of the attack is unclear. Examination of the scene of the incident and of the victims provide clues that are used to determine the nature of the attack.
A number of compounds cause choking or irritation of lung tissue. Examples include chlorine, phosgene (carbonyl chloride), diphosgene, chloropicrin, ethyldichloroarsine, and perflurorisobutylene.
Chlorine gas is suffocating and quickly burns tissues in the nose, mouth, and lungs. The burned tissue can die and slough off, causing lasting damage. Chlorine gas dissipates in the air very quickly. If exposure is not too long, than damage can be minor. In contrast, the compound called disphosgene is a liquid at room temperature, and so persists much longer.
Blister agents cause the formation of large and painful blisters on the skin. Eye and lung tissue can also be damaged. A well-known example of a blistering agent dating from World War I is mustard gas . The damage to cells of the skin cause blistering up to 24 hours after exposure to mustard gas. These blisters take a long time to heal and can send the body into a lethal shock reaction.
Other examples of blistering agents include nitrogen mustard, lewisite, and phenyldichloroarsine. The latter compound is a liquid, which can be sprayed onto an enemy or released from a balloon, helicopter, or airplane.
Blood agents interfere with the body's ability to transport oxygen in the bloodstream. This is done by either blocking the use of oxygen by cells in the body or by blocking the ability of the blood to take up the oxygen. Examples include hydrogen cyanide (also called prussic acid), cyanogen chloride, arsine, carbon monoxide, and hydrogen sulfide.
Hydrogen cyanide is initially a liquid at room temperature, but it quickly evaporates. This compound is noteworthy in recent world history, as it was used by Iraq in 1988 on an attack on the Kurdish town of Halabja during the Iran-Iraq war. Because of its past use by Iraq, hydrogen cyanide was one of the major concerns of United Nations inspectors who inspected various facilities in Iraq during the winter of 2003.
Compounds such as arsine and carbon monoxide destroy the ability of the hemoglobin component of the blood to bind oxygen. Arsine does this by destroying the red blood cells. Carbon monoxide binds to hemoglobin, blocking the binding of oxygen.
Nerve agents interfere with the body's transmission of nerve impulses. This is done by disrupting the activity of a chemical called acetyl cholinesterase, which functions to bridge the gap between adjacent nerve cells, permitting an electrical nerve signal to pass from one nerve cell to the next.
Nerve agents were first developed in 1936, following the development of organophosphate types of pesticides. The first nerve agent that was made is called tabun . It is a member of what is known as the G series of nerve agents. Other G series members are sarin and soman. Sarin is particularly lethal; a small amount absorbed through the skin can kill someone within two minutes. When inhaled, death occurs within 15 minutes. Sarin is infamous as the gas released into the Tokyo subway system by the fringe group Aum Shinrikyo in 1995.
Another series of nerve agents are called the V series. Members of this series—which are commonly abbreviated according to their chemical composition—are more potent than the agents of the G series. As well, they persist longer in the environment. They can, for example, be applied to surfaces like roads as a slime.
Examples of V series agents include VX, VE, VG, and VM. VX is extremely potent; a drop of the liquid absorbed through the skin is lethal within a few hours if treatment is not provided.
Herbicides are chemicals that kill vegetation. Such chemicals are often used in everyday life to keep lawns free of weeds (although more environmentally-friendly alternatives are becoming popular). When used in war, herbicides are weapons of mass destruction to foliage. Destruction of plants and the resulting loss of leaf cover remove much of the concealment for an enemy in a forested area. These philosophies lead to the massive use of Agent Orange by the United States in the Vietnam War in the 1970s. Since that war, the damaging effects of herbicides like Agent Orange and paraquat on the human nervous and immune systems have become evident.
Incendiaries are chemicals that cause fires. In warfare, they are also used to remove vegetation. An infamous incendiary is napalm. Napalm is a mixture of naphthenic acid, coconut fatty acids, and palm oil. In addition to its highly flammable property, napalm absorbs into exposed skin, where it can cause severe burns if ignited.
see also Chemical and biological detection technologies; Water contamination.