On the NFPA hazard diamond, which color denotes reactivity hazards?

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

Answer: (C)

Recognizing the color coding in the NFPA 704 hazard diamond is essential to quickly assess a material’s hazards. In that diamond, blue represents health hazard, red represents flammability, yellow represents reactivity, and white is for special hazards. The reactivity quadrant tells you how likely the material is to undergo a hazardous chemical change—its stability, how it might react with heat, pressure, or other substances, and whether it could decompose violently or polymerize under certain conditions. The numbers in each colored section (0 to 4) indicate the severity, with higher values meaning greater risk. The white section can carry symbols for specific hazards like oxidizers or water reactivity. So, the color denoting reactivity hazards is yellow.