A fire in the Iroquois Theater in Chicago, Illinois, kills more than 600 people on December 30, 1903. It was the deadliest theater fire in U.S. history. Blocked fire exits and the lack of a fire-safety plan caused most of the deaths.

The Iroquois Theater, designed by Benjamin Marshall in a Renaissance style, was highly luxurious and had been deemed fireproof upon its opening in 1903. In fact, George Williams, Chicago’s building commissioner, and fire inspector Ed Laughlin looked over the theater in November 1903 and declared that it was “fireproof beyond all doubt.” They also noted its 30 exits, 27 of which were double doors. However, at the same time, William Clendenin, the editor of Fireproof magazine, also inspected the Iroquois and wrote a scathing editorial about its fire dangers, pointing out that there was a great deal of wood trim, no fire alarm and no sprinkler system over the stage.

During the matinee performance of December 30, while a full house was watching Eddie Foy star in Mr. Bluebeard, 27 of the theater’s 30 exits were locked. In addition, stage manager Bill Carlton went out front to watch the show with the 2,000 patrons while the other stage hands left the theater and went out for a drink. It was a spotlight operator who first noticed that one of the calcium lights seemed to have sparked a fire backstage. The cluttered area was full of fire fuel–wooden stage props and oily rags.

When the actors became aware of the fire, they scattered backstage; Foy later returned and tried to calm the audience, telling them to stay seated. An asbestos curtain was to be lowered that would confine the fire but when it wouldn’t come fully down, a panic began. It later turned out to be made of paper so it wouldn’t have helped in any case. Soon, all the lights inside the theater went out and there were stampedes near the open exits. When the back door was opened, the shift of air caused a fireball to roar through the backstage area.

The teenage ushers working the theater fled immediately, forgetting to open the locked emergency exit doors. The few doors that were able to be forced open were four feet above the sidewalk, which slowed down the exiting process. Most of the 591 people who died were seated in the balconies. There were no fire escapes or ladders to assist them and some took their chances and jumped. The bodies were piled six deep near the narrow balcony exits. In fact, some people were knocked down by the falling bodies and were eventually pulled out alive from under burned victims.

In the aftermath of the disaster, Williams was later charged and convicted of misfeasance. Chicago’s mayor was also indicted, though the charges didn’t stick. The theater owner was convicted of manslaughter due to the poor safety provisions; the conviction was later appealed and reversed. In fact, the only person to serve any jail time in relation to this disaster was a nearby saloon owner who had robbed the dead bodies while his establishment served as a makeshift morgue following the fire.