Which four categories are represented in the NFPA 704 rating system?

• A. Health, Flammability, Reactivity, and Special Hazards
• B. Health, Toxicity, Reactivity, and Stability
• C. Hazards, Exposure, Frequency, and Duration
• D. Protection, Prevention, Containment, and Recovery

Answer: (A)

The NFPA 704 rating system conveys material hazards using four categories: Health, Flammability, Reactivity, and Special Hazards. Each category corresponds to a colored section of the diamond (blue for Health, red for Flammability, yellow for Reactivity, and white for Special Hazards) and a number or code that signals the severity or specific caution. This setup lets responders quickly gauge how dangerous a substance is in terms of potential harm to people, how easily it can catch fire, how it may react under certain conditions, and any special handling notes.

The correct choice matches these four categories exactly. The other options mix terms that aren’t part of the NFPA 704 framework—for example, toxicity or stability aren’t the official NFPA categories, and the others describe aspects like exposure, frequency, duration, or emergency response actions rather than the hazard categories themselves.