🔍 Key Concepts

• Class D (combustible metal) fires and what makes them different from Classes A, B, C • How magnesium reacts with water and CO2 when burning • Why some agents work by smothering vs. cooling vs. chemical reaction

💭 Think About

• Ask yourself: Is magnesium an ordinary solid, flammable liquid, electrical fire, or something else? Which fire class does that belong to? • Think about what happens if you put water or CO2 on burning magnesium—does it actually make the fire worse? • Which agent can form a crust or blanket over burning metal to cut off oxygen without reacting dangerously with the metal?

✅ Before You Answer

• Confirm which option is commonly recommended for Class D–combustible metal fires • Eliminate any agents that can break down into oxygen or react violently with burning magnesium • Make sure the agent you pick will smother and isolate the burning metal rather than spread molten metal or create explosive gas