Which agents are identified as choking agents?

Choking agents refer to chemical agents that primarily cause damage to the respiratory system, leading to a sensation of choking and difficulty breathing. Chlorine and phosgene are classic examples of these agents.

Chlorine gas, used in World War I, is known for its yellow-green color and has a distinct smell reminiscent of bleach. Upon inhalation, it can lead to severe irritation in the airways, pulmonary edema, and potentially death if exposure is significant. Phosgene, though less detectable due to its lack of a strong odor at lower concentrations, is even more potent and can cause serious lung damage and respiratory failure.

In contrast, the other choices consist of different types of chemical agents. GB and VX are classified as nerve agents, which affect the nervous system rather than primarily causing choking. HD (mustard gas) is a blistering agent that damages the skin and respiratory tract in a different manner, while CK is a less commonly referenced blister agent. Distilled mustard, although harmful, does not fit the classification of choking agents as it primarily causes blistering rather than choking sensations. Thus, the correct identification of choking agents aligns with the characteristics of chlorine and phosgene, directly affecting respiratory functions.