In the NEPA 704 rating system, what does the letter W indicate on the label?

In the NEPA 704 rating system, what does the letter W indicate on the label?

• A. Reactive with water
• B. Water-based hazard
• C. Warning
• D. Weight percent

Answer: (A)

In NFPA 704, the white area of the diamond is for special hazards. A W here flags a water-reactive substance. That means the material can react with water, potentially releasing heat, hydrogen gas, or other hazardous products. Because of that, water or water-based extinguishing agents should not be used on or near it; responders use appropriate non-water extinguishing media and take precautions to avoid contact with water. The other options aren’t standard NFPA 704 indicators, or describe different concepts, so they don’t fit this symbol.

In NFPA 704, the white area of the diamond is for special hazards. A W here flags a water-reactive substance. That means the material can react with water, potentially releasing heat, hydrogen gas, or other hazardous products. Because of that, water or water-based extinguishing agents should not be used on or near it; responders use appropriate non-water extinguishing media and take precautions to avoid contact with water. The other options aren’t standard NFPA 704 indicators, or describe different concepts, so they don’t fit this symbol.