🔍 Key Concepts

• Petroleum vapors behavior compared to air (heavier or lighter) • Where heavier-than-air vapors tend to move and accumulate on a vessel • Fire and explosion risks in enclosed or low-lying spaces on ships

💭 Think About

• Think about what happens to a gas that is heavier than air—does it rise and disperse or sink and collect somewhere? • On a ship, what areas are lowest relative to the waterline where gases could settle if they are heavier than air? • Which option, if ignored, would clearly increase the risk of fire or explosion on board?

✅ Before You Answer

• Identify which answers contradict the idea that vapors are heavier than air (those are likely wrong). • Check which choice mentions a location on a vessel where heavier gases can accumulate rather than dissipate. • Eliminate any option that suggests petroleum vapors are not a concern under common weather conditions.