The chemical agent diphosgene, designated as DP, belongs to which family of agent?

Diphosgene, classified under the category of choking agents, is primarily known for its effects on the respiratory system. When inhaled, it reacts with the body's tissues and can lead to severe respiratory distress, fluid build-up in the lungs, and ultimately, suffocation if not treated promptly. This work on the respiratory system aligns it closely with agents designed to disrupt normal breathing functions.

In contrast, nerve agents target the nervous system, causing issues such as muscle paralysis and respiratory failure through inhibition of the enzyme acetylcholinesterase. Blood agents interfere with the body's ability to use oxygen at the cellular level, often leading to hypoxia, and blister agents primarily cause severe skin and respiratory tract damage by forming blisters. While these agents are all highly toxic, diphosgene’s primary mechanism of action and resulting symptoms distinctly categorize it as a choking agent.