Which statement is true about the symptoms of chemical agents?

A sudden onset of symptoms is typical for many chemical agents. This characteristic is crucial to understanding how chemical agents affect victims and underscores the urgency of immediate response measures. When exposed to certain chemical agents, individuals can experience rapid and severe health effects, ranging from difficulty breathing to neurological symptoms, depending on the type and concentration of the agent. This rapid onset allows first responders to identify potential chemical incidents and initiate appropriate actions, such as evacuation or medical treatment, without significant delay.

In contrast, the other statements do not accurately reflect the nature of chemical agent exposure. Symptoms generally do not take weeks to appear; most agents produce effects almost immediately. The statement about only some agents showing symptoms is misleading, as many chemical agents trigger a range of observable effects almost directly after exposure. Similarly, the assertion that symptoms are always mild is incorrect; many chemical agents can cause severe and potentially life-threatening reactions. Thus, the rapid onset of symptoms is a hallmark of chemical exposure and necessitates prompt action.