Gasoline vapors are:

• A. Gasoline vapors are lighter than air
• B. Gasoline vapors have the same density as air
• C. Gasoline vapors are not present
• D. Gasoline vapors are heavier than air

Answer: (D)

Gasoline vapors are heavier than air, so they tend to settle and accumulate in low areas rather than rise. This happens because the vapor molecules from gasoline have a higher average molecular weight than the main components of air, making the vapor density greater than that of air. As a result, vapors can pool along floors, in basements, or near drains, and they can travel along surfaces to ignition sources. Understanding this helps explain why ventilation and controlling ignition sources are crucial to prevent vapor buildup and potential fires.