A fire broke out in a six-story building in the Dotonbori district of Osaka, originating near an outdoor air conditioning unit on the first floor. The blaze spread upward along exterior advertising panels and extended to an adjacent seven-story building. Two firefighters died from suffocation approximately 10 minutes after arriving on the scene while attempting to extinguish the fire. Autopsies confirmed the cause of death as suffocation within the burning building. The Osaka City Fire Department has established an accident investigation committee to determine the cause of the fire, with a preliminary report expected by the end of October. Investigations suggest the fire may have been caused by a short circuit or overheating of the air conditioning unit's motor, a known risk especially during summer and winter months. The fire's unusual spread along the building's exterior and previous administrative warnings have raised concerns about fire safety measures. Witnesses described a sudden flame near the air conditioning unit, and the incident has prompted calls for increased caution regarding outdoor air conditioning units to prevent similar accidents.