Chemical warfare agents are defined as chemical substances introduced for use in military operations to kill, seriously injure, or otherwise incapacitate men through pathophysiologic effects. Riot control agents, such as tear gas, herbicides, smoke, or flame have been excluded by their definition. In recent years the use of riot control agents has been extended to the harassment of guerrillas, commonly to flush them out of hiding places. Many chemical warfare agents are produced inexpensively and easily, and can be stored indefinitely. It has been and remains difficult to verify and control the manufacturing, acquisition, and storage of precursor chemicals used to produce these agents, making it difficult to police them. These characteristics have made chemical warfare agents a major threat worldwide and have led to their being used clandestinely by terrorist groups on civilian populations as well as by organized military during war.
The US is testing weapons to incinerate biochemical agents on impact, using special high temperature shells on specially designed smart bombs. Other incineration technologies are also being developed for civilian installations and chemical stockpiles.
In 1993, the Chemical Weapons Convention has prohibited chemical weapons for all, and required the destruction of existing stockpiles. The treaty's negotiation took 24 years.
The essential feature of the Chemical Weapons Convention is its universality; no great power is allowed to keep the stockpiles. It also means that since the limit is set to zero, it makes the task of verifying compliance clear and precise.
Chemical weapons are the poor man's counterbalance to his neighbours who possess nuclear weapons.