CBRN hazards are classified into two types, what are they?

• A. Primary and Secondary Hazards
• B. Acute and Chronic Hazards
• C. Initial and Final Hazards
• D. Immediate and Residual Hazards

Answer: (D)

In a CBRN incident, hazards are understood in terms of when they present risk and how long they persist: immediate hazards are the dangers right during the release and in the immediate aftermath, while residual hazards are the contamination or hazards that remain in the environment after the initial event and require decontamination and longer protection measures.

This framing helps responders plan actions like safe entry, use of PPE, and decontamination steps. The other options describe time frames or concepts that don’t match this common classification in CBRN contexts, whereas immediate and residual hazards specifically capture both the initial danger and what remains to be managed afterward. For example, a toxic gas released creates an immediate hazard; contaminated surfaces or lingering radiation create residual hazards that must be addressed through decontamination and containment.