The class of goods most likely to cause a fire when not packaged correctly is flammable or combustible materials (often called Class 3: Flammable Liquids in hazardous materials classification).Flammable goods such as gasoline, alcohol, solvents, or other chemicals can easily ignite if exposed to heat, sparks, or friction. Improper packaging can lead to leaks, spills, or exposure to air, increasing the risk of combustion or fire. These materials require special packaging to prevent vapor release and to protect them from physical damage during transport and storage.