What is the highest numerical rating for any category on the NFPA 704 diamond?

What is the highest numerical rating for any category on the NFPA 704 diamond?

• A. 0
• B. 1
• C. 4
• D. 3

Answer: (C)

NFPA 704 uses three hazard categories—health, flammability, and instability—each rated on a 0 to 4 scale. A higher number means greater severity. The highest possible rating in any category is four, indicating a severe hazard that requires stringent precautions. Therefore, the maximum numerical rating you can see on the diamond is four. The white area shows special hazards and doesn’t carry a numeric value, so it doesn’t affect the 0–4 scale.

NFPA 704 uses three hazard categories—health, flammability, and instability—each rated on a 0 to 4 scale. A higher number means greater severity. The highest possible rating in any category is four, indicating a severe hazard that requires stringent precautions. Therefore, the maximum numerical rating you can see on the diamond is four. The white area shows special hazards and doesn’t carry a numeric value, so it doesn’t affect the 0–4 scale.