Dangerous When Wet Hazard Sign - Class 4.3 Safety Symbol Explained #63436 (License: Personal Use)

This blue diamond-shaped label is the official UN GHS-compliant symbol for Class 4.3 dangerous goods: substances that react with water to release flammable gases (e.g., sodium, potassium, calcium carbide). The black flame icon above the bold text “DANGEROUS WHEN WET” and the numeral “4” at the bottom clearly identify the hazard class and specific risk. It is required on packaging, transport vehicles, and safety data sheets for regulated materials.

Used in logistics, chemical manufacturing, warehousing, and transportation sectors to warn handlers of water-reactive hazards; aligns with OSHA, DOT, and IMDG regulations for user intent around safety compliance and emergency response.