What color indicates Class D fires, which involve combustible metals?

Class D fires are associated with combustible metals such as magnesium, titanium, and sodium. The correct indication for Class D fires is yellow. This color is specifically used to symbolize the presence of combustible metals and the unique hazards they present when they ignite. Yellow signage helps responders quickly identify the type of materials involved and take appropriate action. Class D fires cannot be extinguished with water; in fact, using water can worsen the fire, which emphasizes the importance of recognizing the correct color code in emergency situations.