Introduction

Chemical agents are poisonous gases, liquids or solids that have toxic effects on people, animals or plants. Chemical incidents are characterized by the rapid onset of medical symptoms and easily observed signatures, such as colored residue, dead foliage, pungent odor and dead animals and insects. Most chemical agents cause serious injuries or death. They are classified by their effects: nerve, blood, choking or blister. These weapons kill by destruction or disruption. The infamous "gases" of World War I --mustard gas, for instance -- essentially burn away parts of the respiratory system. More modern nerve gases --Tabun, Sarin and VX -- disrupt the chemical processes through which one nerve cell communicates with another. Severity of injuries depends on the type and amount of the chemical agent used, and the duration of exposure.

Chemical agents are generally liquid when containerized but are disseminated as an aerosol or gas. To be effective, chemical agents must be dispersed in sufficient quantity to cause serious damage. These agents are heavily influenced by weather conditions, such as temperature, wind speed and direction, humidity and air stability, that make it difficult to achieve sufficient concentrations to be effective in an open-air environment. Unlike biological and radiological weapons, chemical agents are fast acting. Protection from these agents requires full respiratory and skin protection.

Were a chemical agent attack to occur, authorities would instruct residents to either seek shelter where they are and seal the premises or evacuate immediately. Exposure to chemical agents can be fatal. Leaving the shelter to rescue or assist victims can be a deadly decision. There is no assistance that the untrained can offer that would likely be of any value to the victims of chemical agents.

In this section, we discuss sarin gas, mustard gas, VX and tabun.