Which hazard is associated with Class 4 flammable solids?

Which hazard is associated with Class 4 flammable solids?

• A. They are never water reactive.
• B. They are always non-toxic.
• C. Some are spontaneously flammable.
• D. They extinguish easily.

Answer: (C)

Some flammable solids in Class 4 can ignite on their own in air, without an external ignition source. This spontaneous ignition risk is a real hazard for materials in this class, especially when they are finely divided or dusty. It means a fire can start simply from exposure to air, not just from flames, sparks, or heat. Within Class 4 there are subdivisions that cover this risk, as well as other hazards like reacting with water to produce flammable gases. So while some materials may ignite spontaneously, others might react with water or have different toxicity profiles. That’s why the statement about spontaneous flammability best captures a true hazard associated with Class 4 flammable solids.

Some flammable solids in Class 4 can ignite on their own in air, without an external ignition source. This spontaneous ignition risk is a real hazard for materials in this class, especially when they are finely divided or dusty. It means a fire can start simply from exposure to air, not just from flames, sparks, or heat.

Within Class 4 there are subdivisions that cover this risk, as well as other hazards like reacting with water to produce flammable gases. So while some materials may ignite spontaneously, others might react with water or have different toxicity profiles. That’s why the statement about spontaneous flammability best captures a true hazard associated with Class 4 flammable solids.