(1) Carbon dioxide Explanation: A fire extinguisher, flame extinguisher, or simply an extinguisher, is an active fire protection device used to extinguish or control small fires, often in emergency situations. Typically, a fire extinguisher consists of a hand-held cylindrical pressure vessel containing an agent which can be discharged. to extinguish a fire. Cartridge-operated extinguishers contain the expellant gas (usually carbon dioxide) in a separate cartridge that is punctured prior to discharge, exposing the propellant to the extinguishing agent.