The most disastrous theatre fire of the modernist era was the one in which over 600 people died at the Iroquois Theatre (seating capacity 1,724) on Randolph Street in downtown Chicago. At the sold-out matinee performance of Mr. Bluebeard, starring Eddie Foy, on 30 December 1903, a spark from a calcium arc light in the flies above the stage ignited a drop curtain there. The asbestos curtain snagged and could not be lowered. When somebody opened the loading doors to the alley, the rush of air caused the flames to blow out to the auditorium. Foy was long remembered as the hero of the occasion for his efforts to keep the audience from panicking. When theatergoers reached the inexplicably locked exit doors, they pushed and piled up in a crush. Others were asphyxiated in their seats. The ensuing investigation of what had happened in the "absolutely fireproof" theatre resulted in numerous reforms to ensure safety in theatres.
See also Theatre fires.
The Historical Dictionary of the American Theater. James Fisher.