Which extinguishing agent is not generally recommended for Class D metal fires?

• A. WATER
• B. SAND
• C. DRY CHEMICAL
• D. FOAM

Answer: (D)

Metal fires require a extinguishing approach that interrupts the reactions happening at the surface of the burning metal. The best option is a dry powder specifically designed for Class D fires, because it coats the metal, absorbs heat, and disrupts the chemical reaction between the metal and oxygen. Foam isn’t suitable because it’s water-based and introduces moisture, which doesn’t effectively cool or isolate the hot metal and can even spread burning metal or trigger dangerous reactions. In contrast, sand can sometimes smother or bury the fire when a proper Class D powder isn’t available, but foam does not provide the right protection for these fires.