Which of the following is classified as a blister agent?

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

Answer: (B)

Mustard (HD) is classified as a blister agent due to its ability to cause severe skin blisters upon contact. Blister agents, also known as vesicants, are chemical compounds that result in painful skin lesions and damage to internal tissues when they come into contact with the skin or are inhaled.

Mustard agents, specifically, can lead to long-term health effects, including damage to the respiratory system and an increase in the risk of cancer due to the nature of the chemical's interaction with body tissues. Historically, mustard gas was used in warfare, and its recognition as a blister agent is based on its recognized effects on those exposed to it.

In contrast, the other substances listed are classified differently; Sarin and Tabun are nerve agents that disrupt the normal function of the nervous system, while hydrogen cyanide is a blood agent that interferes with cellular respiration. Understanding the classification of these agents is crucial for responding effectively to hazardous materials incidents.