The fire was first noticed around 10:15 p.m. in the Melody Lounge, which was located in the basement. According to witnesses, it immediately spread throughout the Melody Lounge between the false cloth ceiling and the plywood ceiling above it, then ascended the stairway.
According to District Fire Chief John P. Vahey’s November 1970 report to the Fire commissioner:
As the fire rushed up the stairway it traveled near the ceiling and above the heads of the persons ascending to make their way out of the building. The movement of this fire and great volume of carbon monoxide gas generated by lack of oxygen was accelerated by the narrow (4 feet) width of stairway which acted like a chimney adding a draft of suction to the room below. In the stairway the partially unburned gas rapidly mixed with air and increased the temperature and rapidity of flow.
The burning mass passed from the top of the stairway into a narrow connecting corridor. At this end of the corridor was an exit door leading to Piedmont Street (this door was locked the night of the fire). The other exit from the melody Lounge was by means of a door (used by waiters) leading to a passageway to the kitchen. Located in this passageway was a door leading to an outside alleyway. (This door was locked the night of the fire).
Fire appeared in the street floor lobby within two to four minutes after it was first seen in the Melody Lounge. It was described as traveling rapidly as a “ball of fire” below the ceiling and a yellowish or blue color.
Most of the lights on the premises became extinguished immediately upon the appearance of the fire.
The fire in the corridor of the Foyer appeared to have been accelerated by a large ventilating fan placed over the further end of the Caricature Bar acting to draw air from the Foyer along the length of the Caricature Bar.
As fire traveled through the lobby toward the Caricature Bar it was soon followed by a thick cloud of smoke. The fire then traversed the length of the area containing the Caricature Bar.
Some few persons, including persons coming from the basement Melody Lounge passed through the revolving door on Piedmont Street before the mass of flames reached it. The door then appears to have jammed. There was a very great pouring of flames through the exit. The great majority of persons on the street floor had no warning of the fire until the flames actually appeared in the lobby.
Upon reaching the Main Dining Room the flame, moving rapidly, swept high about the room near the ceiling, shortly followed by a cloud of dense smoke described by witnesses as acrid.
The burning and decomposition of wall coverings once again produced material largely gaseous and capable of further combustion and vary rapid movement.
The great mass of partially burned gases spread from the Main Dining Room and into the Broadway Lounge.
The rapidly pouring mass of burning gaseous material appeared to have been depressed from its high elevation within the premises in order to pass through the exits. Persons attempting to pass through the exits were overcome by the great heat of fire and of the gaseous material pouring through them at the time.
The fire, within five minutes after it was first seen in the basement room, entirely traversed the street floor of the main building and had passed to the entrance to the Broadway Lounge.
Until such time as they were brought under control, the flames poured out of the exits on Piedmont Street, Shawmut Street and Broadway.
The firefighters had the fire out in little over an hour. The cause of the fire was never determined, and according to the Boston Fire Department’s official report, the origin of the fire is indicated as ”unknown.”