Which of the following is NOT a nerve agent?

Mustard gas is not classified as a nerve agent; rather, it is considered a blister agent. It primarily affects the skin and respiratory system, causing severe blistering and tissue damage. The mechanism of action of mustard gas involves the formation of lesions and destruction of mucosal membranes, which is distinct from the way nerve agents operate.

In contrast, nerve agents such as Sarin (GB), VX, and Tabun (GA) work by inhibiting the enzyme acetylcholinesterase, leading to an accumulation of acetylcholine in the synapses. This results in overstimulation of the nervous system, causing a range of symptoms from muscle twitching to respiratory failure and potentially death. Understanding the differences in the mechanisms and effects of these chemical agents is crucial for responders and military personnel in order to properly identify and respond to chemical threats.