Which defensive control technique is a barrier used to physically contain liquid within a designated area?

• A. Retention
• B. Dike
• C. Diversion
• D. Ventilation

Answer: (B)

Containment with a physical barrier. A dike is a built barrier—earth, sandbags, or other material—placed around a spill to form a closed or semi-closed perimeter. This creates a contained area where the liquid cannot easily spread, making it safer and easier to control and clean up.

Retentions describe the area that holds the liquid after it’s stopped, which is related but not the barrier itself. Diversion redirects flow away from sensitive zones rather than surrounding the spill. Ventilation moves vapors and air, not the liquid, so it doesn’t provide containment.