Which color on the NFPA 704 label indicates health hazard rating?

• A. Blue section of NFPA 704
• B. NFPA 704 label
• C. Yellow section of NFPA 704
• D. Heat, fuel, and oxygen needed for combustion

Answer: (A)

Blue is the color used for the health hazard rating on the NFPA 704 label. The NFPA 704 diamond uses four colored sections to convey different hazard types: blue for health, red for flammability, yellow for reactivity, and white for special hazards. Each colored section carries a number from 0 to 4 that indicates the severity of that hazard, with 0 meaning no hazard and 4 meaning a severe risk. So the health hazard rating is read from the blue area, which is why blue is the correct choice.

The other colors correspond to different hazards: red indicates flammability, yellow indicates reactivity, and white is for special hazards. The phrase about heat, fuel, and oxygen relates to the fire triangle concept, not to the color coding on the NFPA 704 label.