What monitoring occurs when the CBRN device is not used at the source of a CBRN hazard?

• A. Direct Monitoring
• B. Remote Monitoring
• C. Indirect Monitoring
• D. Route Reconnaissance

Answer: (C)

When you can’t place a monitoring device at the hazard itself, you rely on information that points to the hazard without measuring it directly. Indirect monitoring uses secondary evidence or data gathered away from the source to infer what the hazard is and how strong it might be. This approach is common in CBRN reconnaissance because it keeps personnel out of danger while still providing actionable insights—like analyzing environmental samples, plume movement with wind data, or other signs that indicate the presence and characteristics of the hazard.

Direct monitoring would require measuring right at the source, which isn’t being done here, and remote monitoring, while from a distance, still involves sensing from a fixed position rather than inferring from indirect indicators. Route reconnaissance focuses on surveying paths and routes rather than evaluating the hazard itself, so it’s not the monitoring mode described.