If a combustible metal such as magnesium is on fire, what should you use to extinguish it?

Using a Class D fire extinguisher for a fire involving combustible metals like magnesium is the appropriate choice because these extinguishers are specifically designed for use on fires involving flammable metals. Class D extinguishers contain agents that can smother or cool the fire without reacting adversely with the burning metal, which is crucial since water or other common extinguishing agents can exacerbate such fires.

Magnesium burns at extremely high temperatures and can react violently with water or other substances. Therefore, a Class D extinguisher is equipped with dry powder agents, such as sodium chloride or graphite, that can effectively suppress the flames and prevent re-ignition without causing dangerous reactions.

In contrast, using a general fire extinguisher may not effectively extinguish a metal fire and could pose additional risks. Similarly, a Class K fire extinguisher, which is intended for cooking oils and fats, is not suited for metal fires. Thus, having access to and knowing how to use a Class D extinguisher is essential for safely handling combustible metal fires.