Fires involving combustible metals, such as magnesium, titanium, zirconium, sodium, and potassium are fires.

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (D)

Fires involving combustible metals burn at extremely high temperatures and can react violently with water or common extinguishing agents. Metals like magnesium, titanium, zirconium, sodium, and potassium require a different approach than ordinary fire types. Because of these unique properties, metal fires are categorized separately as Class D. The extinguishing method uses a dry powder extinguishing agent designed for metals, which coats and cools the metal to interrupt the reaction with air without triggering dangerous reactions. Water or other standard extinguishing methods can cause explosive or violent reactions with these metals, so they’re avoided. Understanding that metal fires fall under Class D is why this choice is the best.