Which statement is TRUE regarding chemical agents?

The correct statement emphasizes that a small quantity of a chemical agent can result in significant harm, potentially leading to a large number of casualties. This highlights the potent nature of chemical agents, which can be designed to be extremely effective even in minimal doses. Additionally, it accurately states that chemical agents can exist in multiple states: solid, liquid, or gas. This versatility allows chemical agents to be deployed in various environments and conditions, enhancing their potential impact.

The other statements do not hold true based on the properties and risks associated with chemical agents. For instance, the idea that chemical agents only come in gas form is incorrect, as many of them can also be effective in liquid or solid forms. Furthermore, stating that chemical agents are harmless in small quantities contradicts the fundamental concern regarding their potential lethality, even with limited exposure. Therefore, the accurate recognition of the nature and potential consequences of chemical agents reinforces the importance of proper training and preparedness in handling hazardous materials.