chemical agent (e.g., hydrogen cyanide, allyl chloride) that is absorbed into the general circulation system and carried to all body tissues. These agents deprive tissue cells of oxygen, even though the blood is capable of carrying oxygen. The brain, being highly dependent upon a continual source of oxygenation, is especially susceptible. Clinical signs include hyperventilation, which further enhances the dose received, resulting in abrupt cardiovascular collapse.

A blood agent is a chemical warfare agent that is inhaled and absorbed into the blood, carrying the agent to all body tissues where it interferes with the tissue oxygenation process. The brain is especially affected. The effect on the brain leads to cessation of respiration followed by cardiovascular collapse.[49

A chemical agent that interferes with the ability of blood to transport oxygen and causes asphyxiation.  These substances injure a person by interfering with cell respiration (the exchange of oxygen and carbon dioxide between blood and tissues).  Examples are hydrogen cyanide and cyanogen chloride.