180. If a powdered aluminum fire is being fought, which is the most effective extinguishing agent to use?

Dry powder is the correct extinguishing agent for powdered aluminum fires because these fires, classified as Class D (combustible metals), require a specialized dry powder that smothers the fire and avoids dangerous reactions with the metal; water, steam, water fog, and CO2 are ineffective and potentially hazardous due to their ability to react violently or be displaced by the fire's heat.