Which NFPA 704 color indicates flammability hazards?

• A. Blue
• B. Red
• C. Yellow
• D. White

Answer: (B)

The main idea here is how NFPA 704 communicates different hazard types with color-coded quadrants. Each color block on the diamond represents a specific kind of risk: blue for health hazards, red for flammability, yellow for reactivity/instability, and white for special hazards (like oxidizers or water reactivity).

The red block is the one that indicates flammability hazards. It shows how easily the material can ignite and sustain combustion, with a numerical scale from 0 to 4 where higher numbers mean greater flammability risk. A material rated high in flammability can ignite readily under common conditions, while a low rating means it’s much less likely to ignite.

So, when assessing the sign or label, the color indicating flammability hazards is red.