The larger the region covered by the chemical agent, the more likely it will be to cause the widespread destruction for which the person or group is looking (Brophy & Fisher, 1959). Toxicity matters, of course, but the earliest uses were not about the level of toxicity the chemical agent possessed. They were more focused on how the toxic was absorbed. If the chemical agent could be absorbed through the clothing and skin, a gas mask would be useless against it and it would be more likely to work on a larger number of people (Burck & Flowerree, 1991). July of 1917 saw the use of mustard gas begin (Brophy & Fisher, 1959). The Germans, once again, were the first to use this chemical. It easily passes through fabric and leather, and causes very painful burns to appear on the skin. There are two categories into which chemical agents like mustard gas can fall: incapacitating and lethal (Janata, 2009). There is no fixed distinction between the two, but there is a statistical average that is used to make a determination. Additionally, substances are deemed incapacitating if it takes less than 1/100th of a lethal dose to cause said incapacitation (Janata, 2009). Often, the method of incapacitation is through visual problems, nausea, or something similar that the person will recover from but that will make traveling, fighting, and other tasks difficult for a period of time (Brophy & Fisher, 1959; Janata, 2009).

One of the ways in which chemical agents are classified has to do with the persistency they have. This is a measurement of the time they remain effective after they have been disseminated (Janata, 2009). The agent is either considered persistent or non-persistent. When they are considered to be non-persistent they use effectiveness very quickly. It can take minutes are hours to render these agents completely ineffectual, and sometimes it takes only seconds, depending on the chemical agent in question (Hammond, 1999). Chlorine gas, for example, is a non-persistent chemical agent. Sarin is also non-persistent and highly volatile, as are most other nerve agents. When a person or group needs to take a target "by storm" and gain control very quickly, these kinds of non-persistent agents are the best ones to use. They incapacitate or kill the targets, but because they disperse so quickly they allow those who are taking over to move in without waiting around for some of the targets to escape or recover enough of their faculties to potentially be able to fight back.

The delivery mode that is used is nearly as important as the agent where chemical warfare is concerned (Burck & Flowerree, 1991; Haber, 1986). Deployment of a non-persistent agent should be similar to the fine droplets that an aerosol can produces. That allows the gas to be inhaled, but it also allows the mist to be absorbed through the pores and into the skin (Haber, 1986). That is much more toxic to the target than a larger mist that the skin will not accept. High concentrations are needed to be effective, and a single breath should contain enough of the agent to be lethal (Hammond, 1999; Janata, 2009). Ballistic missiles that have cluster warheads or rocket artillery and bombs are the two best ways to get the agent to the target and deploy it in such a way as to be sufficient to achieve this level of saturation (Janata, 2009). This is a far different approach than would be used for persistent agents which, as their name implies, can remain in the target area for a long period of time and be highly difficult to clean up and neutralize (Janata, 2009).

Biological Warfare

Biological warfare is very different from chemical warfare, although the end result and the goal is the same. In biological, or germ, warfare, the agents used commonly include viruses, bacteria, and fungi (Alibek & Handelman, 2000). These are used with the intent to either incapacitate or kill human beings, plants, or animals when employed as an act of war. Other names for these agents include bio-weapons, bio-agents, or biological threat agents (Endicott & Hagerman, 1998). They are organisms that are alive and they are designed to replicate or reproduce within their hosts (Appel, 2009; Crosby, 1986). Occasionally, insects have also been used for warfare. Because of their living nature and means of replication, they are considered to be biological warfare agents. There are different ways in which biological agents are employed in warfare. Sometimes they are actually used, and other times they are just threatened (Appel, 2009). Often, the threat of biological warfare is enough...

They can be either lethal or non-lethal, and they are often targeted against large groups. However, small groups, individuals, or en entire population would not be immune (Dembek, 2007). Non-national groups and nation states can develop, acquire, stockpile, and deploy biological agents. When nation states use biological agents in a clandestine manner, or when non-national groups use them, it is often categorized as bioterrorism (Endicott & Hagerman, 1998). There are some overlaps between chemical and biological agents, because toxins that are produced by organisms that are alive fall under both the Chemical Weapons and Biological Weapons Conventions (Alibek & Handelman, 2000). Psychochemical weapons and various toxins are also available, and are generally called midspectrum agents (Alibek & Handelman, 2000; Appel, 2009).
Unlike the true biological agents, these agents that fall into the midspectrum range are characterized by shorter period of incubation and are not able to reproduce in their host (Endicott & Hagerman, 1998). While they are sometimes not as lethal because of these limitations, it is not safe to assume that they cannot be deadly or highly incapacitating under the proper circumstances. The use of biological weapons was outlawed in 1972, and this ruling meant that they also could not be mass produced or stockpiled (Alibek & Handelman, 2000). As of 2011, 165 countries had ratified that treaty. The goal is to ensure that countries cannot use a biological attack to create large numbers of casualties in the civilian population and cause disruptions to social and economic infrastructures (Alibek & Handelman, 2000). While the creation of these agents is prohibited, studying how to protect oneself from them and create a defense if they were ever to be used is not prohibited. Many countries pursue the study of biological warfare in this manner.

Biological weapons are highly destructive not just because of what they can do but because of how small an amount of them is needed in order to do anything that would result in a significant loss of life (Crosby, 1986; Dembek, 2007). Even more than nuclear, conventional, or chemical weapons, biological weapons cause a heavy level of destruction quickly and with only a small amount of agent (Crosby, 1986). They cost relatively little to develop and are easily stored, making them very useful as a deterrent when strategy is being discussed. On the battlefield they make good offensive weapons (Alibek & Handelman, 2000; Endicott & Hagerman, 1998). Even though it is illegal for countries to continue to make or store them, it is highly likely that there are still stockpiles of biological warfare agents in numerous countries - especially those that did not ratify the treaty. While this cannot be proven, it is something about which the other countries have to be aware.

Throughout history, there have been many examples of biological warfare. As far back as the 6th century BC, there were tales of the Assyrians putting a fungus into the drinking water of their enemies in order to make those enemies delirious (Alibek & Handelman, 2000). Hannibal of Carthage used biological warfare in 184 BC when he had his troops throw pots filled with venomous snakes onto the decks of enemy ships (Alibek & Handelman, 2000). Medieval Europe also has many accounts of biological agents being used. Infected animal carcasses were used to poison water supplies of enemies, and these diseased carcasses were also used as projectiles in catapults that were being used to launch them into cities under siege. The last known use of infected corpses as biological warfare was in 1710 (Alibek & Handelman, 2000). As society advanced, biological warfare changed and developed. There is at least one documented case of the British Army attempting to use smallpox as a biological agent. They army gave blankets that were infected with the disease to the Lenape during Pontiac's War (Endicott & Hagerman, 1998). There are also suspicions that this same type of tactic was used on the Native Americans, but this has never been proven.

In WWI, anthrax and other agents really started to be developed and used. Bacteriology and germ…