NFPA 704 diamonds convey hazard information in which three primary categories?

• A. Density, Color, Viscosity
• B. Temperature, Pressure, Humidity
• C. Health, Flammability, Reactivity
• D. Safety, Handling, Security

Answer: (C)

NFPA 704 diamonds communicate hazard through three main dimensions: health, flammability, and reactivity. Each dimension has a numeric rating from 0 to 4 that indicates how severe the hazard is in that aspect—higher numbers mean greater risk. The health rating tells you how dangerous exposure or contact is to people, the flammability rating shows how easily the material can ignite, and the reactivity rating indicates how violently the material might react under certain conditions. There’s also a separate area on the left for special hazards (like oxidizers or water reactivity), but the three primary categories described by the numerical ratings are health, flammability, and reactivity.