What is the first step in operating a fire extinguisher?

The first step in operating a fire extinguisher is to pull the pin. This action is crucial as it unlocks the extinguisher and allows the user to discharge the extinguishing agent. The pin is a safety device designed to prevent accidental discharge; therefore, it must be removed before any other action can be taken. Once the pin is pulled, the user can then proceed to aim the nozzle or horn at the base of the fire, squeeze the operating lever, and sweep the extinguishing agent across the fire to effectively put it out. Properly following this sequence is essential for safely and effectively using a fire extinguisher.