Which hazard class is represented by the placard illustration labelled 'Poison gases'?

• A. Dangerous when wet
• B. Radioactives
• C. Poison gases
• D. Corrosives

Answer: (C)

Poison gases indicate a toxic inhalation hazard—the material is a poisonous gas that can cause severe health effects or death if inhaled. This is a toxic gas classification, so the placard signals the need for measures to prevent inhalation exposure, such as appropriate respiratory protection and ventilation when handling or transporting. The other labels point to different hazards: “dangerous when wet” describes substances that react violently with water, radioactive materials carry a radiation hazard, and corrosives cause severe burns or damage to skin, eyes, or metals. Because the label explicitly says poison gases, the correct interpretation is a toxic gas hazard.