Which option correctly names the identifying feature of the vapor dome roof tank?

• A. Giant bulge on top
• B. Ladder extending to center of the roof
• C. Two roofs: Tank cover and floating roof
• D. Flat top with no features

Answer: (B)

The key idea here is recognizing exterior cues that identify tank roof configurations. For a vapor dome roof tank, the defining feature is a ladder that extends to the center of the roof. This central access point signals the presence of a dome structure atop the fixed roof and is the practical cue responders look for to classify this tank type and anticipate related hazards or procedures. While a dome shape might be noticeable, the central ladder is the clear, distinctive indicator. The option describing two roofs points to a different setup (like a covered or floating roof arrangement), and a flat top with no features would not match a vapor dome design.