Cast the Runner-Up: The original script gave the fire chief a smaller role, which was offered to Ernest Borgnine while Steve McQueen was offered the role of the architect. McQueen insisted on playing the fire chief and thus the part was expanded.
Paul Newman regretted doing the movie after the intense rivalry between himself and his co-star Steve McQueen.
William Holden referred to the film as "lousy". He also complained about his part – "I spend all of the time talking on the phone."
Robert Vaughn got so tired of his role being cut down during filming he requested to be killed off earlier in the film so he could marry Linda Staab. He also barely mentions his experience working on the film in his autobiography.
Dueling-Stars Movie: They actually invented Diagonal Billing just for this movie, due to the star power of its leads Steve McQueen and Paul Newman, who were professional rivals at the time.
The film was shot in sequence so the actors looked honestly haggard and dirty as it went on.
In a scene where a bunch of people are fighting to get onto an elevator, the extras were really fighting to keep off the elevator, since anyone who did get on it was pretty much done, and anyone who stayed off it was guaranteed a job for the next couple of months.
This ended up getting played with, as one extra with a mustache and glasses and wearing a ruffled light blue tuxedo shirt is seen escaping on the scenic elevator before the power cuts off, yet the character is then seen multiple times throughout the rest of the film, and gets a bit of a closeup as one of the trapped partygoers who has tied himself to a railing prior to the water tank explosion.
Also, the first lady in the buoy is among the first 10 that were to escape in the group that goes to the roof for the helicopter evacuation, which means that when Roberts rigs the scenic elevator to go down for the final time, she should have been in THAT group, since it is made up of the entire roof group, Lisolette, and fireman Mark Powers, yet inexplicably, she's not in there and thus is available for the scene when they first use the breeches buoy.
In the scenic elevator scene, the explosions were bigger than the actors were anticipating, so they really were panicking.
Desperate to capture a truly surprised reaction from the cast, Irwin Allen actually fired a handgun into the ceiling without warning the actors, who were understandably "surprised". The trick worked and he got his shot.
Fred Astaire was genuinely terrified during the explosions, so his look of fright is real.
Many people consider the film to be The Poseidon Adventure only with a burning building.
The film inspired writer Roderick Thorp to write the 1979 book Nothing Lasts Forever, but changed it to a single policeman fighting terrorists. Nothing Lasts Forever was adapted into the film Die Hard.
According to actor/stuntman Ernie F. Orsatti, Faye Dunaway was often late to the set or didn't appear at all. This made some scenes impossible to film and caused other actors such as William Holden and Jennifer Jones to become quite upset, culminating in Holden reportedly shoved Dunaway against the wall one day and threatened her. For the next month, she had a perfect attendance record.
Inverted with Paul Newman and Steve McQueen, who were professional rivals but got along very well on the set.
Faye Dunaway and Steve McQueen left strict instructions they should not be approached by visitors to the set. McQueen also refused to give interviews. Paul Newman asked only that he not be "surprised".
Life Imitates Art: A real fire broke out on set, and Steve McQueen found himself briefly helping out real firefighters. One of them didn't recognise him and said "my wife isn't going to believe this", to which Steve responded "neither's mine."
"For the 1st time, I fell for the goddamn numbers. I did this turkey for a million and 10% of the gross, but it's the first and last time, I swear."
No Stunt Double: Steve McQueen and Paul Newman did most of their own stunts, including the former having several gallons of water dropped on him and the latter climbing up and down the bent stairwell railing. McQueen also performed the stunt where he leaps off a helicopter onto the top of the burning building against Irwin Allen's wishes. This is likely why Allen used a shot of McQueen being lowered from the back, obscuring his face, so it looks like the shot was created with a stuntman anyway, since Allen includes an obvious cut before McQueen's face is revealed among the flames on the roof.
Richard Chamberlain made a career out of playing heroes, anti-heroes or sensitive guys. Here he's the Jerkass.
By this point Robert Vaughn was mostly playing villains, however here he plays a heroic character. Subverted somewhat in the sense that the role of Sen. Parker was initially intended to be a secondary antagonist, but during filming, all of Parker's antagonistic traits were transferred to Simmons' character, which ended up turning Parker into a hero.
Production Posse: Many bit players from The Poseidon Adventure also star here. Notably Callahan is played by the actor who was Poseidon's chief engineer and calls Linarcos a bastard, while Wes is the ship's crewman in Poseidon who says his mistress "is the sea," and dies telling Hackman's character to get to the lifeboat stations.
The pink satin cape worn by the mayor's wife was part of a costume worn by Jean Simmons in Desiree.
The large sculpture in the Promenade Room was used in Hello, Dolly!.
Real-Life Relative: Paul Newman's son Scott stars as a fireman. This is the only film they did together. Unfortunately, they don't share any scenes together.
Referenced by...: The classic 1977 hit "Disco Inferno" by The Trammps had lyrics that riffed on the film, specifically the discothèque scenes and the whole burning skyscraper motif (except it happens because "the funk was flamin' out of control").
Science Marches On: Since the making of this film, there was the notorious MGM Grand Hotel fire when it was discovered and publicized once and for all that in a major structure fire, it's not the flames themselves that is the major killer, it's the smoke. Ironically, in both The Glass Inferno and The Tower many of the casualties do indeed die of smoke inhalation, especially those on the top floor, near the end of the story.
Star-Derailing Role: While the film itself was far from a failure and did wonders for Newman's career, its massive success resulted in Steve McQueen, at the time the highest-paid and most desirable actor in Hollywood, deciding to take a four-year hiatus from acting, during which he turned down offers for the leading roles in One Flew Over the Cuckoo's Nest, The Bad News Bears, and even Close Encounters of the Third Kind. By the time he returned to the silver screen in 1978, the film industry had long since moved on to newer stars and the role offers had all but dried up. His first film after coming back, an adaptation of An Enemy of the People, tested so poorly that its release was initially canceled and while it was eventually "released" to one theater, it was entirely accidental due to someone sending them the wrong reels. His final two movies were Tom Horn and The Hunter, a Western and a car-based action film, which were closer to the roles people expected of him, but both failed critically and financially before he passed away from lung cancer in 1980.
Wag the Director: Steve McQueen, a veteran of this trope by then, requested that he and Paul Newman have the exact same amount of lines in the film. Also he insisted that he not appear until forty three minutes in, by which point Newman would have used up a lot of his lines. William Holden attempted to – demanding he be billed first. But as he'd been in a few flops lately, he gets third billing.
Irwin Allen wanted to direct the entire movie himself, but studio executives wouldn't allow it. Allen was permitted to helm the action sequences, however.
Raquel Welch was considered for the role of Susan. Natalie Wood was approached too, but declined as she was pregnant at the time. She also found the script "mediocre". She didn't have similar reservations several years later when she appeared in the disaster film Meteor.
Simmons was killed by trying to escape to the stairs in the original script.
Fred Astaire lobbied to write a song for the film, but his effort was deemed to be too old-fashioned, making the way for "We May Never Love Like This Again".
In early drafts of the script, the role of Senator Parker was a secondary antagonist along with Simmons, and seems to have been given the traits of Congressman Cary Wycoff from the novel The Tower. As is stated above, Simmons was to die in the escape attempt on the stairs, and Parker was to try to commandeer the breeches buoy and be killed off. However, during filming, the negative aspects of Parker's character were given to Simmons, and while it made Sen. Parker into the heroic character he is in the film, it also substantially reduced Robert Vaughn's role in the film, and wanting to get married to his future wife, Linda Staab, Vaughn requested to exit filming earlier.
Tying in with the above, the final shooting script would have had Mayor Ramsey be the one who was killed attempting to stop Simmons from stealing the breeches buoy, and Senator Parker was intended to be the character killed during the water tank explosion sequence. Robert Vaughn requested that the deaths of Parker and Ramsey be flip flopped so he could leave filing earlier to marry Linda Staab, and thus instead of Parker almost making it to the end, as was intended, he is killed off midway through the third act and it's Ramsay who gets killed off during the water tank explosion finale.
James Franciscus and John Forsythe were the original choices for Sen. Gary Parker. However, it was felt that they too closely resembled then-Sen. John Tunney and then-Gov. Ronald Reagan. Since one was a Democrat and the other a Republican, they decided that they wanted to leave politics out of it, so the role as offered to Robert Vaughn, who had no resemblance to anyone political at the time (although he was well known for his political activism against the Vietnam War at that time).
General Trivia:
In the documentary film of the real events of 9/11, a man in the street looks up at the World Trade Center burning and says "...this is just like The Towering Inferno, like in a movie."
While this film was playing at the El Rey Theatre in California, a real fire struck on August 6th 1975. The poster survived the fire and is still on display at the Manteca Museum.
There were about four different units filming at once, due to the large scale of the production.
Case Closed creator Gosho Aoyama cites this movie as a personal favorite, and part of the inspiration for the series' first movie, The Time-Bombed Skyscraper.
