If the white area of the NFPA diamond affixed to a container has a "W" on it, what should you be careful about when working with that substance?

• A. Make sure you only handle it under water.
• B. Avoid exposing it to water.
• C. Do not use if it has turned white.
• D. None of the above

Answer: (A)

When the white area of the NFPA 704 placard shows a W, it flags a water-reactive substance. Water contact can trigger a dangerous reaction, generating heat, gases, or even an explosion. That means you must avoid exposure to water and keep the material dry during handling, storage, and cleanup.

Practically, don’t use water to extinguish a fire involving this material; instead, use appropriate dry extinguishing agents per the SDS. Store and handle the substance in a moisture-free environment, keep containers tightly closed, and use dry absorbents or neutralizers if a spill occurs. In short, the key precaution is to prevent any water or moisture from contacting the material.