Which of the following is NOT a Class 3 hazard?

• A. Gases
• B. Flammable liquids
• C. Combustible liquids
• D. None of the above

Answer: (A)

Class 3 hazards are flammable liquids. The key idea is that hazard classes group materials by how they can ignite or burn, and for liquids that means looking at their flash point. Flammable liquids have a flash point low enough to ignite easily, so they fall into Class 3. Combustible liquids, while harder to ignite, are still considered part of the flammable-liquid category in many regulatory schemes because they pose an ignition hazard associated with liquids.

Gases are classified separately as Class 2 because their danger comes from being in a gaseous state—vapors and dispersed gas can ignite and spread rapidly, and that behavior is not the same category as liquids with low flash points.

Therefore, the material that is not a Class 3 hazard is the gas, since its hazard class is Class 2.