Dangerous When Wet Hazard Sign - Class 4.3 Safety Symbol Explained #2218653 (License: Personal Use)

The image shows a standardized GHS/UN hazard pictogram: a blue diamond with a black flame over a horizontal line, bold text “DANGEROUS WHEN WET”, and the class number “4” at the bottom. It identifies materials that emit flammable gases upon contact with water-such as alkali metals, metal hydrides, or carbides-and require strict moisture control during storage and transport. This symbol is mandated by OSHA, DOT, and IMDG for labeling containers and placarding vehicles carrying such substances.

Used on chemical safety data sheets (SDS), shipping containers, transport vehicles, and storage facilities to alert handlers, emergency responders, and regulators to water-reactive hazards; matches user intent for hazard identification, compliance training, or safety protocol development.