Charles Boyer was originally cast as "Prof. Montel."
In his review of the film, New York Times critic Bosley Crowther misquoted the foreword, implying that the film was based on a true story in which announcements about an explosion had been made by the White House and Atomic Energy Commission.
The film was initially banned in France "on political grounds." An article noted that France had also banned Soviet films with political themes, and that "a number of European countries are sensitive to films with political themes and refuse them exhibition permits rather than rouse the ire of either the U.S. or Russia."
The scene from the attack on the first island was taken from the movie Crash Dive. Particularly the ammo exploding in the depot and the burning fuel cascading over the short cliff into the sea.
This marked the feature film debut of Darryl F. Zanuck's muse Bella Darvi, whose stage surname was a combination of the first names of Zanuck and his wife Virginia.
This was Twentieth Century-Fox's fifth CinemaScope production.