CW Agents

Blood
Blood agents are absorbed into the body primarily by breathing. These agents poison an enzyme called cytochrome oxidase, blocking the use of oxygen in every cell. By preventing the normal transfer of oxygen from the blood to body tissues, the agent rapidly affects all tissues, especially the central nervous system. The very high volatility of the blood agents makes them less useful as CW, but their low persistency also has its advantages.

Choking
Choking agents were among the first CW armaments produced in large quantities, and were used extensively in World War I. Inhaled in sufficient quantities, choking agents produce pulmonary edema, ultimately suffocating the victim in his own fluids. Of the choking agents, chlorine and phosgene are the best known.

Nerve
Nerve agents are extremely toxic chemicals that were developed in secrecy before and during World War II, primarily for military use. Nerve agents kill by paralyzing the respiratory musculature and can cause death in minutes. These agents vary in persistence, with some compounds creating a short-term battlefield hazard and other compounds lingering for days or weeks.

Vesicants
Vesicants are the most widely used and stockpiled CW agent and include the best-known CW agents: Mustard and Lewisite. These agents are likely to be used both to produce casualties and to force opposing troops to wear full protective equipment thus degrading fighting efficiency, rather than to kill, although exposure to such agents can be fatal. These agents burn and blister the skin or any other part of the body they contact, acting on the eyes, mucous membranes, lungs, skin and blood-forming organs. The agent damages the respiratory tract when inhaled and causes vomiting and diarrhea when ingested.