The Boston Fire Department investigated possible causes of ignition, the rapid spread of the fire and the catastrophic loss of life. Its report reached no conclusion as to the initial cause of ignition, but attributed the rapid, gaseous spread of the fire to a buildup of carbon monoxide gas due to oxygen-deprived combustion in the enclosed space above the false ceiling of the Melody Lounge. The gas exuded from enclosed spaces as its temperature rose and ignited rapidly as it mixed with oxygen above the entryway, up the stairway to the main floor and along ceilings. The fire accelerated as the stairway created a thermal draft, and the high-temperature gas fire ignited pyroxylene (leatherette) wall and ceiling covering in the foyer, which in turn exuded flammable gas. The report also documented the fire safety code violations, flammable materials and door designs that contributed to the large loss of life.