William Holden was hospitalized for six days during the production of the film to treat his alcoholism after director James Goldstone convinced producer Irwin Allen that Holden was a danger to himself and others in the cast.
In his autobiography, Ernest Borgnine claimed that the reason the film's special effects looked so cheap was because so much of the budget went toward location shooting.
Toward the end of his life, Paul Newman confessed in interviews that this was the only film that he ever made entirely for the money. He called it "that volcano movie" and said that he and most of the cast knew right away it would be a flop from day one. Many people believe that part of his salary from this film was used as seed money for a salad dressing business he was setting up with A.E. Hotchner, with 100% of the profits, after taxes, going to educational and charitable organizations. As of 2022 Newman's Own, the company that Newman established in 1982, has raised over $550 million for charities all over the world, and continues to grow and prosper.
Paul Newman, William Holden, Veronica Hamel, Ernest Borgnine, and Red Buttons were all under contract with Irwin Allen, and appeared in this film only to fulfill those contracts.
Steve McQueen was under contract to Irwin Allen. After refusing a part in "The Towering Inferno 2," that film was scrapped and Paul Newman was brought in to make this film. McQueen died soon after.