The hazard class represented by the placard illustration that indicates Dangerous When Wet is which class?

The hazard class represented by the placard illustration that indicates Dangerous When Wet is which class?

• A. Dangerous When Wet
• B. Combustibles
• C. Health Hazard
• D. Oxidizers

Answer: (A)

The placard text “Dangerous When Wet” identifies a specific hazard within Hazard Class 4. It points to Class 4.3, which covers materials that react with water to release flammable gases or heat and can ignite or detonate. That’s why this label is interpreted as the danger class shown. The other options refer to different classes—combustibles to other 4.x hazards, Health Hazard to Class 6, and Oxidizers to Class 5.1—so they don’t match the explicit phrasing on the placard. Substances like calcium carbide illustrate this class well, reacting violently with water.

The placard text “Dangerous When Wet” identifies a specific hazard within Hazard Class 4. It points to Class 4.3, which covers materials that react with water to release flammable gases or heat and can ignite or detonate. That’s why this label is interpreted as the danger class shown. The other options refer to different classes—combustibles to other 4.x hazards, Health Hazard to Class 6, and Oxidizers to Class 5.1—so they don’t match the explicit phrasing on the placard. Substances like calcium carbide illustrate this class well, reacting violently with water.