Which label indicates ignition is possible under almost all ambient temperatures for a substance in liquid or solid form?

• A. Ignition Source
• B. 3 Flammability diamond
• C. Oxidizer
• D. Fuel

Answer: (B)

Ignition tendency under normal temperatures is shown by the flammability rating on the NFPA 704 label. A high flammability rating in the red section means the material can be readily ignited at almost any ambient temperature, which is characteristic of liquids and solids that burn easily. That specific label directly communicates how easily ignition can occur across typical environmental conditions, making it the best choice for indicating ignition potential under almost all ambient temperatures.

The other labels point to different aspects: ignition source describes what heat or spark is needed to start burning, an oxidizer is a substance that supports combustion, and a fuel is the material that actually burns. None of these convey how temperature affects ignition likelihood the way the flammability rating does.