Which of the following is NOT a category used to classify chemical agents?

• A. Physiological
• B. Military use
• C. Volatility
• D. Onset effects

Answer: (C)

When thinking about how chemical agents are categorized, the focus is on how the agent affects humans and how it’s used. You categorize by physiological effects (what it does to the body, such as nerve vs blister agents), by military use (whether it’s used as a weapon or for other purposes), and by onset of effects (how quickly symptoms appear). Volatility, while important for understanding how easily a substance becomes vapor and thus how it might spread in the environment, is a physical property rather than a category that defines the agent’s action or its military role. It influences exposure risk and protective measures, but it doesn’t group agents by mechanism or intended use. That’s why volatility isn’t a standard classification category, making it the correct choice for not belonging to those classification categories.