In the context of CBRN incident response, which zone contains the highest contamination risk and requires decontamination personnel and PPE?

• A. Cold zone
• B. Warm zone
• C. Hot zone
• D. Transition zone

Answer: (C)

In CBRN incident response, zones are used to separate areas by contamination risk and control access. The zone with the highest contamination risk is the hot zone, where responders work directly with the contaminant. In this area, full protective gear is required and decontamination personnel operate to remove contaminants from people and equipment before they move to cleaner zones. Surrounding the hot zone is the warm zone, which handles initial decontamination and PPE changes, offering a buffer with significant—but lower—risk than the hot zone. The cold zone remains the clean area for command, medical care, and support. The key idea is that the hot zone is the most contaminated—necessitating specialized PPE and active decontamination efforts.