The building's top three floors[11] were occupied by the Triangle Shirtwaist Factory, owned by Russian immigrants Max Blanck and Isaac Harris.

Rooms were overcrowded with few working bathrooms and no ventilation, resulting in conditions ranging from sweltering heat to freezing cold.

The rooms in the upper three floors were packed with flammable objects, including clothing products hanging from lines above workers' heads, rows of tightly spaced sewing machines, cutting tables bearing bolts of cloth, and linen and cotton cuttings littering the floors,[11] that resulted in a massive spread of fire occurring in the matter of seconds.

[citation needed] A survivor of this incident indicated that there had been a blue glow coming from a bin under a table where 120 layers of fabric had just been stacked prior to cutting.

Fire rose from the bin, ignited the tissue paper templates hung from the ceiling, and spread across the room.

Others died because they jumped out the building's windows to escape the flames – the interior stairs were blocked and the elevators stopped functioning properly because of the heat.

[12] The factory owners Max Blanck and Isaac Harris were charged with “criminal negligence”,[11] and faced multiple lawsuits from the victims’ families.

[19] It is internally connected to the adjacent Silver Center and Waverly buildings, and make up the "Main Block" of NYU.