How should operators confirm the area is clear?

• A. Audible warning
• B. Visual marks only
• C. Verbal confirmation only
• D. Manual counting

Answer: (A)

Before blasting, you need a signal that reaches every worker in the blast area. An audible warning serves this purpose best because it travels through noise and doesn’t depend on sight. Visual marks can be missed, verbal confirmation alone can be misheard in a loud environment, and counting people isn’t reliable if someone is out of place or not accounted for. The audible warning provides a clear, shared cue for everyone to evacuate or stay out, helping ensure the area is truly clear before the operation proceeds.