Solids that are readily combustible or that may cause or contribute to fire through friction, including self-reactive substances and desensitized explosives that can explode if not sufficiently diluted, are classified as which division?

• A. Flammable Solids
• B. Readily Combustible Solids
• C. Fire Hazard Solids
• D. Explosive Substances

Answer: (A)

The main idea here is how solids are sorted by fire hazard for transport. Division 4.1 covers flammable solids—solids that are readily combustible or can ignite and contribute to a fire, including situations where friction can start ignition. The phrase in the statement—solids that are readily combustible or may fire up through friction—is the textbook description of flammable solids. The note that self-reactive substances and desensitized explosives can explode if not sufficiently diluted is included to show that, for regulatory purposes, certain materials with explosive potential in solid form are still treated under this same division because their primary hazard in transport is fire/explosion risk rather than a conventional liquid flammable hazard.

So, the correct division is Flammable Solids. The other terms don’t align with the official classification language used for this category, which is why they aren’t the best fit.