In NFPA 704 placards, which color indicates Reactivity hazard?

In NFPA 704 placards, which color indicates Reactivity hazard?

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

Answer: (C)

NFPA 704 uses a diamond with four colored sections to convey different hazard types at a glance. Each color corresponds to a specific category: blue for Health, red for Flammability, yellow for Reactivity, and white for Special information. The Reactivity hazard is indicated by the yellow section. The number inside that yellow area (0–4) shows how reactive the material is, with higher numbers meaning greater potential for hazardous changes under heat, shock, friction, or contact with water. The yellow color is used specifically to alert responders to instability or reactivity concerns separate from health or fire risks.

NFPA 704 uses a diamond with four colored sections to convey different hazard types at a glance. Each color corresponds to a specific category: blue for Health, red for Flammability, yellow for Reactivity, and white for Special information. The Reactivity hazard is indicated by the yellow section. The number inside that yellow area (0–4) shows how reactive the material is, with higher numbers meaning greater potential for hazardous changes under heat, shock, friction, or contact with water. The yellow color is used specifically to alert responders to instability or reactivity concerns separate from health or fire risks.