A chemical weapon agent (CWA) is a chemical substance whose toxic properties are used to kill, injure or incapacitate human beings. About 70 different chemicals have been used or stockpiled as chemical weapon agents during the 20th century. These agents may be in liquid, gas or solid form.
In general, chemical weapon agents are organized into several categories according to the physiological manner in which they affect the human body. Division may also be by tactical purpose or chemical structure. The names and number of categories varies slightly from source to source, but in general, types of chemical warfare agents are as follows.
these are substances that are not intended to kill or injure. They are often referred to as Riot Control Agents (RCAs) and may be used by civilian police forces against criminals and rioters, or in the military for training purposes. These agents also have tactical utility to force combatants out of concealed or covered positions for conventional engagement, and preventing combatants from occupying contaminated terrain or operating weapons. In general, harassing agents are sensory irritants that have fleeting concentration dependent effects that resolve within minutes after removal. Casualty effects are not anticipated to exceed 24-hours nor require medical attention.Chemical weapons use has been outlawed worldwide for over 90 years and outlawed comprehensively through the 1997 Chemical Weapons Convention (CWC), which bans all development, production, and deployment of deadly chemical arms and requires the verifiable destruction of remaining stockpiles