In NFPA placards, the letter B indicates

• A. Health hazards
• B. Biological hazards
• C. Boiling hazards
• D. Biochemical hazards

Answer: (A)

NFPA placards convey hazard information using a color-coded diamond, and the blue section specifically represents health hazards. The number inside that blue area (0–4) indicates how severe the health risk is. The other colors cover different categories—red for flammability, yellow for reactivity, and the white section for special hazards. Since the option that matches what the blue health-hazard area represents is “health hazards,” that is the correct concept. The other choices—biological hazards, boiling hazards, and biochemical hazards—are not categories used in NFPA 704 labeling.