Which of the following is a blood agent?

• A. Mustard (HD)
• B. Sarin (GB)
• C. Chlorine
• D. Hydrogen cyanide

Answer: (D)

Hydrogen cyanide is classified as a blood agent, which refers to a group of chemical agents that interfere with the body's ability to utilize oxygen. When blood agents are inhaled or absorbed, they quickly enter the bloodstream and bind with hemoglobin, preventing the transport of oxygen to tissues. This can lead to asphyxiation and potentially fatal outcomes.

In contrast, mustard (HD) is a blistering agent that primarily causes damage to skin and mucous membranes, leading to painful blisters rather than directly affecting the blood's capacity to carry oxygen. Sarin (GB), on the other hand, is a nerve agent that disrupts the nervous system function by inhibiting an enzyme important for proper nerve signaling. Chlorine is a choking agent that primarily affects the respiratory system, causing damage to the lungs and airways rather than directly impacting blood function. These other agents exhibit different mechanisms of toxicity, focusing on their respective effects rather than asphyxiation through blood interaction like hydrogen cyanide.