What does the NFPA 704 safety diamond indicate and what are the four color-coded ratings?

• A. Hazard ratings; blue = health, red = flammability, yellow = instability, white = special information.
• B. Hazard ratings; red = health, blue = flammability, white = instability, yellow = special information.
• C. Colors: blue indicates heat, red indicates stability, yellow indicates health, white indicates flammability.
• D. Hazard ratings indicate only fire risk.

Answer: (A)

The main idea is that the NFPA 704 diamond is a quick-reference hazard rating system, not just a fire risk indicator. It uses four colored sections to convey different kinds of danger so responders can assess a chemical at a glance.

• Blue section: health hazard. It shows how dangerous a substance is to your health if you’re exposed. The numbers 0–4 (0 being no hazard, 4 the highest) communicate the severity.

• Red section: flammability. This tells you how easily the material can catch fire.

• Yellow section: instability (reactivity). This indicates how likely the substance is to undergo a dangerous reaction or release energy under normal conditions, including shock or heat.

• White section: special information. This area carries symbols or letters about hazards that don’t fit the other categories (for example, oxidizers, water reactivity, or radioactivity).

So the correct interpretation is that the diamond provides hazard ratings, with blue for health, red for flammability, yellow for instability, and white for special information. The other options mix up the color mappings or limit the purpose to fire risk, which is not accurate for NFPA 704.