[3] Only the destruction of the World Trade Center on September 11, 2001, claimed more lives in a disaster affecting an American building.

[5] The fire broke out at about 3:15 p.m. while the Iroquois presented a matinee performance of the musical Mr. Blue Beard starring Eddie Foy.

The syndicate that bankrolled its construction chose the location specifically to attract women visiting the city on day trips who would be more comfortable attending a theater near the police-patrolled Loop shopping district.

[6] The theater opened on November 23, 1903, after numerous delays resulting from labor unrest[7] and, according to one writer,[6] the unexplained inability of architect Benjamin Marshall to complete required drawings on time.

Upon opening, the theater was lauded by drama critics; Walter K. Hill wrote in the New York Clipper (a predecessor of Variety) that the Iroquois was "the most beautiful ... in Chicago, and competent judges state that few theaters in America can rival its architectural perfections ..."[8] The Iroquois had a capacity of 1,602 with three audience levels.

Despite being billed as "absolutely fireproof" in advertisements and playbills,[12] numerous deficiencies in fire readiness were apparent in the theater building.

An editor of Fireproof Magazine toured the Iroquois during construction and noted "the absence of an intake, or stage draft shaft; the exposed reinforcement of the (proscenium) arch;[13] the presence of wood trim on everything and the inadequate provision of exits.

"[14] Chicago Fire Department (CFD) captain Patrick Jennings performed an unofficial tour of the theater days before the official opening and noted that there were no sprinklers, alarms, telephones or water connections.

Sallers did not report the matter directly to fire chief William Musham, concerned that he would be dismissed by the syndicate that owned the theater.

When Captain Jennings reported the matter to his commanding officer, battalion chief John J. Hannon, he was told that nothing could be done as the theater already had a fireman.

[17][18] On Wednesday, December 30, 1903, the Iroquois presented a matinee performance of the popular Drury Lane musical Mr. Blue Beard, which had been playing at the theater since opening night.

[19] At about 3:15 p.m., shortly after the beginning of the second act, eight men and eight women were performing the double-octet musical number "In the Pale Moonlight", with the stage illuminated by blue-tinted spotlights to suggest a night scene.

[21] A chemist who later tested part of the curtain stated that it was composed mainly of wood pulp mixed with asbestos and would have been "of no value in a fire.

"[19] Foy was widely considered a hero after the fire for his courage in remaining on stage and pleading with patrons not to panic even as large chunks of burning scenery landed around him.

Some had found the fire exits hidden behind draperies on the north side of the building but discovered that they could not open the unfamiliar bascule locks.

Bar owner Frank Houseman, a former baseball player with the Chicago Colts, defied an usher who refused to open a door.

Houseman credited his friend outfielder Charlie Dexter, who had just quit the Boston Beaneaters, with forcing open another door.

When the door was opened, an icy wind blast rushed inside, fueling the flames with air and causing the fire to grow substantially larger.

A passing railroad agent saw the crowd pressing against the door and unfastened the hinges from the outside, allowing the actors and stagehands to escape.

The hot gases and flames passed over the heads of those in the orchestra seats and incinerated flammable materials in the gallery and dress circle levels, including patrons still trapped in those areas.

Although iron grates that blocked secondary stairways during performances (to prevent patrons in the cheaper seats from sneaking downstairs to the more expensive lower levels) were still in place, first responders found very few victims near the gates.

Students from the Northwestern University building north of the theater tried bridging the gap with a ladder and then with some boards between the rooftops, saving those few able to manage the makeshift crossover.

[32] The Chicago Police Department became involved when an officer patrolling the theater district saw people emerge from the building in a panic, some with clothing on fire.

Most charges were dismissed three years later because of the delaying tactics of the syndicate's lawyers and their use of loopholes and inadequacies in the city's building and safety ordinances.

As more people escaped via the theater cellar through the sewers, Howey reported his scoop; the story, one of the biggest in Chicago's history, established his reputation for speed, resourcefulness, and skillful writing.

He was later immortalized as the scheming, ruthless managing editor Walter Burns in Ben Hecht and Charles MacArthur's play The Front Page.

The front page of the January 26, 1904 edition of the Washington Evening Star featured a story about the Chicago coroner's jury findings headlined "Harrison arrested".

[52] The Chicago Tribune described the marker on December 31, 1911 as depicting "the Motherhood of the World protecting the children of the universe, the body of a child borne on a litter by herculean male figures, with a bereaved mother bending over it."

[55] The Iroquois fire prompted widespread implementation of the panic bar, first invented in the United Kingdom following the Victoria Hall disaster.

[citation needed] Another result was that all doors in public buildings must open in the direction of egress, but that practice did not become national until the Collinwood School Fire of 1908.