Which of the following is NOT a primary blast effect?

• A. Sound from music.
• B. Overpressure (shock wave).
• C. Fragmentation.
• D. Debris impact.

Answer: (A)

The idea being tested is distinguishing primary blast effects from other blast-related hazards. Primary effects come from the blast overpressure—the rapid pressure rise and fall caused by the detonation that directly loads the body with the shock wave. Overpressure (the shock wave) is a textbook primary effect because it is the direct result of the explosion’s energy moving through air. Fragmentation and debris impact are produced when the device casing breaks apart and fragments fly outward, which makes them secondary hazards. The sound produced by the blast is simply audible energy and, while loud noises can cause hearing damage in some contexts, it is not a direct mechanical consequence of the blast wave on the body like the primary effects. So, sound from music is not a primary blast effect.