Реферат: Biology And Chemical Warfare Essay Research Paper

Biology And Chemical Warfare Essay, Research Paper


Chemical and Biological Warfare, use of harmful or deadly chemical or biological agents as weapons of war. These agents can kill many people and are considered weapons of mass destruction. Chemical weapons are made up of poisonous chemical compounds, whereas biological weapons are living microorganisms. Toxin weapons contain poisonous chemical products of living organisms and are sometimes classified separately. Chemical and biological weapons can cause injury in several ways. Most cause injury or death when inhaled, and some cause injury through contact with skin or through ingestion of contaminated food.

A chemical or biological attack usually involves dispersing agents into the air.

This can be done in various ways, such as firing artillery shells that burst in mid-air, or using airplanes to spray the agents over an area. If released outdoors, these types of weapons can be affected by weather conditions. Rain would reduce the effectiveness of the agents, and wind might spread them in unexpected directions. Because chemical and biological agents are seen as random, dangerous, and particularly cruel weapons, they have rarely been used. In the 20th century, chemicals were used extensively as battlefield weapons only in World War I (1914-1918) and the Iran-Iraq War (1980-1988). The release of the nerve agent sarin in a Tokyo subway in 1995 was a rare terrorist chemical attack.

The 1972 Biological Weapons Convention and the 1993 Chemical Weapons Convention are the most recent international agreements prohibiting these types of weapons, and both have been signed by many countries. Nevertheless, analysts contend that following the Iran-Iraq War, more countries began to secretly develop chemical and biological weapons, and the threat of their use has become greater. Iraq in particular has been accused of stockpiling such weapons, and Iraqi resistance to United Nations weapons inspections in the late 1990s raised international awareness of the need for stronger efforts to control biological and chemical weapons.

II. Chemical WarfarePrint section

Chemical warfare involves the use of chemical compounds to kill or seriously injure an enemy. Several countries began eliminating their chemical weapons stockpiles in the 1990s, but the threat of their use still exists.

A. Chemical AgentsPrint section

Chemical warfare agents can be grouped into two general types: those that affect the body surfaces they contact, and those that damage the general nervous system.

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Surface agents include phosgene gas, chlorine gas, hydrogen cyanide, and mustard gas. The principal action of phosgene, chlorine, and hydrogen cyanide occurs through inhalation. Phosgene is a choking agent that causes the lungs to fill with water, while chlorine destroys the cells that line the respiratory tract. Hydrogen cyanide blocks oxygen from reaching the blood. Mustard gas is actually composed of tiny droplets of liquid that are dispersed in the air, where they are inhaled like a gas. Mustard is a blistering agent that damages any surface it contacts, including the skin, eyes, and lungs. It may cause death by respiratory failure. See also Tear Gas.

Nerve agents act by blocking the transmission of nerve messages throughout the body. These agents include sarin, soman, tabun, and VX. All act by disrupting the normal action of a neurotransmitter called acetylcholine. Whether inhaled or absorbed through the skin, a single drop of nerve agent can shut down the body’s nervous system. The most powerful of this group is VX, but all can cause death within minutes after exposure. See also Nerve Gas.

Herbicides, such as Agent Orange, are chemicals that kill vegetation. Agent Orange was used during the Vietnam War (1959-1975) as a defoliant, destroying jungle leaves to expose enemy troops. Some people regard herbicides as chemical weapons if used for hostile purposes, but there is no universal agreement about this, since herbicides are not directly intended to harm humans or animals. However, veterans of the Vietnam War suffered several health problems blamed on exposure to Agent Orange and other toxins.

B. Early DevelopmentPrint section

Large-scale use of chemical weapons first occurred in 1915 during World War I, when German troops released chlorine gas from cylinders as the wind blew toward French lines a few hundred yards away. The yellow-green cloud enveloped the French soldiers, who choked and panicked. As the war continued, phosgene and other chemical weapons were used, culminating with Germany’s introduction of mustard gas in 1917. By the end of the war in 1918, all the major powers had used chemical weapons.

The suffering caused by the gas attacks led to the 1925 Geneva Protocol, which banned the use of chemical or bacteriological agents in war. Although most major countries became parties to the agreement, the United States declined to until 1975. Nevertheless, the Protocol encouraged an international norm that helped deter the use of these weapons.

C. Recent DevelopmentsPrint section

Use of poison weapons has been alleged in only a few of the hundreds of wars and skirmishes since World War I?and has been verified in even fewer. The handful of proven cases include Italy’s limited use of chemical arms against Ethiopia in the 1930s, and Egypt’s use of chemical agents against Yemen in the 1960s. But the international agreement to eschew such weapons was most flagrantly violated by Iraq during the Iran-Iraq War. Although Iraq denied using chemical weapons, United Nations (UN) inspectors repeatedly found Iraqi forces were doing so. Still, no international agency or country tried to stop Iraq’s actions. As a result, in the 1991 Persian Gulf War, which pitted Iraq against an alliance led by the United States, many nations that had been silent about Iraq’s actions faced an Iraqi army equipped with biological and chemical weapons.

Ground fighting in the Gulf War lasted only a few days, and Iraq apparently did not fire any chemical or biological agents, but the experience prompted renewed attention to the problem of such weapons. In 1995, a Japanese cult called Aum Shinrikyo released sarin nerve agent in the Tokyo subway, killing 12 people and injuring 5500. Cult leaders reportedly told authorities that their choice of weapon was inspired by publicity about Iraq’s chemical arms.

III. Biological WarfarePrint section

Biological weapons are a unique class of weapons, a living organism. These biological agents represent a dangerous military threat because they are alive, and are therefore unpredictable and uncontrollable once released. This is one important reason that biological weapons have rarely been used.

A. Biological AgentsPrint section

Biological warfare agents include bacteria, viruses, fungi, and other living microorganisms that can kill or incapacitate. Since they can reproduce, biological agents have the unique potential to make an environment more dangerous over time. If used for hostile purposes, any disease-causing microorganism could be considered a weapon. For the purposes of warfare, specific characteristics of certain agents make them more likely to be used than others.

Some potential warfare agents can make their victims very sick without necessarily killing them. Examples include the microorganisms that cause tularemia, Q fever, and yellow fever. After suffering debilitating illness, victims of these diseases often recover, although not always. Other agents are more likely to be lethal. The bacteria that cause bubonic plague and the virus that causes smallpox can kill large numbers of untreated people. Early antibiotic treatment usually cures plague victims, and smallpox vaccinations before exposure to the virus can prevent the disease.

Anthrax bacteria are considered likely weapons because of their particular features. They can exist as hardy, shell-like forms called spores. In a warm, moist environment like the human lung, the spores can become active and highly lethal. Anthrax bacteria are usually found under the soil surface, and cause disease primarily in cattle and other grazing livestock. But if released into the air and inhaled, a few thousand spores can be fatal.

Botulinum toxin is also lethal in tiny doses. Although often categorized as a biological weapon, the toxin is not itself a living agent, but a product of the bacterium Clostridium botulinum. The toxin is dangerous whether inhaled or ingested in food or drink. A gallon of botulinum toxin could poison a small city’s water system, but existing water purification systems can neutralize the toxin and protect city dwellers. See also Botulism.

B. Biological Warfare HistoryPrint section

The use of biological weapons has been more rare than the use of chemical weapons. In the 14th century, plague-infected cadavers purportedly were catapulted into an enemy camp in the Russian Crimea. In colonial America, the British delivered blankets from their smallpox infirmary to Native Americans, hoping to infect them with the disease. In the 20th century, the only extensive military biological attacks were by Japan against China in the late 1930s and 1940s. The Japanese dropped plague and other bacteria from airplanes over several towns, causing outbreaks of disease. The only large-scale terrorist attack with a biological weapon occurred in 1984 in the United States. Members of the Rajneesh cult in Oregon placed salmonella bacteria in the salad bars of several restaurants. Although 750 people became ill, none died.

IV. Delivery SystemsPrint section

Chemical and biological agents are most effective when dispersed into the air. These agents are often fitted into bombs or artillery shells that are designed to explode in the air and spread their contents over an enemy. In the 1980s, the United States began to deploy binary chemical weapons. Older chemical shells and bombs housed a single blistering or nerve agent. As they aged, these weapons could leak their poisons. A binary weapon is safer because it contains two relatively harmless chemicals. Only after firing do the chemicals combine to form a potent mix.

In some warfare or terrorist scenarios, an explosive release is not necessary. Members of Aum Shinrikyo attacked the Tokyo subway by packing sarin in plastic containers. To release the nerve agent, they pierced the containers with sharp umbrella tips. The leaking liquid and vapor affected thousands of passengers.

Microorganisms are generally more fragile than chemicals, and some might not survive an explosion. But several, like anthrax spores, do remain potent after an explosive release. In any case, United States Army tests have shown that biological agents can be broadly dispersed in a variety of non-explosive ways. In the 1950s and 1960s the Army released bacteria and chemical particles in hundreds of tests in populated areas throughout the country. Agents were sprayed at San Francisco from a boat offshore, dispensed from slow-moving cars in Minneapolis and St. Louis, and released from light bulbs dropped in the New York subway. The bacteria and chemicals in the tests were not as dangerous as actual warfare agents, although they posed some risks to the exposed populations. They demonstrated that an enemy or terrorist could expose millions of people to disease-causing organisms by a variety of simple techniques.

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