Virtually all fires start small and might be extinguished if the proper type and amount of extinguishing agent were applied.
Fire extinguishers are the first line of defense against fire.
However an alarm should be given and Security notified at x13 as soon as fire is discovered. Notification should never be delayed in the hope that the extinguisher will be sufficient. Pull the pin to activate the handle. Aim the nozzle at the base of the fire. Squeeze the handle to expel the extinguishing agent.