Which NFPA 704 color quadrant is associated with reactivity hazards?

• A. Blue
• B. Red
• C. Yellow
• D. White

Answer: (C)

NFPA 704 uses a four-color diamond to show different hazard types, and each color points to a specific kind of risk. The yellow quadrant is where reactivity hazards are shown, indicating how likely a material is to react violently, release gases, or otherwise become unstable under conditions like heat, shock, or contact with water or other substances. The numbers (0–4) beside it describe how severe that reactivity risk is, from minimal (0) to severe (4). Blue covers health hazards, red covers flammability, and the white section is for special hazards such as oxidizers or water reactivity. So the reactivity risk is indicated by the yellow area.