What is the first step in the PASS application method of operating a portable fire extinguisher?

The first step in the PASS application method for using a portable fire extinguisher is to pull the pin to break the thin wire or plastic seal. This action is crucial because it not only unlocks the extinguisher, allowing the user to operate it, but it also ensures that the fire extinguisher is ready for immediate use. The pin serves as a safety mechanism to prevent accidental discharge, and removing it is necessary before you can move on to the subsequent steps in the PASS technique: aiming the nozzle, squeezing the handle, and sweeping it side to side to effectively suppress the fire.

In understanding the context of the other options, aiming at the fire, squeezing the handle, and sweeping side to side all depend on the initial action of pulling the pin. Without this first step, the extinguisher cannot be engaged properly, rendering further steps ineffective. Thus, pulling the pin is essential and sets the stage for successfully addressing the fire.