Test audiences believed that Dave Karnes (Michael Shannon), the former Marine, was a Hollywood invention. This is, in fact, a true story that occurred. Karnes later re-enlisted in the Marine Corps and served two tours of duty in Iraq. Also, as reported by the Associated Press on August 14, 2006, the Marine identified only as Sergeant Thomas (who disappeared shortly after 9/11) has been identified as Jason Thomas, a former Marine who grabbed his uniform and immediately drove to Ground Zero to help. Because his identity was unknown at the time of filming, Sgt. Thomas - who is black - was portrayed by William Mapother, a white man. The producers have since apologized to Sgt. Thomas for the miscasting. Thomas has laughed it off and told them not to be concerned, stating, "I don't want to shed any negativity on what they were trying to show."
Due to her infamous quote that "America is responsible in some way" for the 9/11 attacks, Maggie Gyllenhaal personally offered to withdraw from the project to Officer William Jimeno and his wife Allison Jimeno. They both declined and gave their blessing for Gyllenhaal to take the role.
In preparing for his portrayal of Sgt. John McLoughlin, Nicolas Cage focused on accurately speaking with a New York accent. And to also capture the fear and claustrophobia of McLoughlin's ordeal, Cage spent hours in a sensory-deprivation tank in Venice, California.
A billboard for Zoolander (2001) is visible in one shot, as the shadow of a hijacked airliner descends over New York City. That film, released shortly after the 9/11 attacks, had images of the World Trade Center digitally removed.
The city of New York absolutely prohibited the recreation of 9/11 destruction or chaos on location. The filmmakers were not even allowed to film actors looking upward toward where the towers would be. The drive of the officers up to the site was permitted to be filmed, but all scenes depicting events at or near the WTC were filmed in Los Angeles.
Officer Scott Strauss, a first responder with the New York City Emergency Services unit, was offered the chance to play himself in the film. However, Strauss refused to do so and Stephen Dorff was then cast to portray him. Strauss's services as a consultant were retained for the film to which he didn't accept payment.
Oliver Stone used many of the East Coast www.PoliceActors.com members to play cops in the film. All members of PoliceActors.com are active or retired members of a Law Enforcement agency who are also Screen Actors Guild members.
Three weeks before its August 9 nationwide release, producer Michael Shamberg and director Oliver Stone held private screenings of the finalized film for Port Authority officers and firefighters who risked their lives at the World Trade Center. The screenings were held in local multiplexes in the New Jersey/New York area.
The highest grossing feature film of the 2000s about the events of September 11th, at over $162 million dollars worldwide. Its opening weekend gross of $18.7 million was the best of Oliver Stone's career.
Oliver Stone thought of casting Kevin Costner as Sgt. John McLoughlin, his JFK (1991) lead. Costner had narrated the 2006 documentary On Native Soil (2006), about the 9/11 Commission Report's investigation of the causes of the terrorist attacks and what could have been done to prevent them from happening. Paramount Pictures was concerned that Stone and Costner would then delve into another conspiracy theory.
The trivia items below may give away important plot points.
Jeanette Pezzulo, the widow of Officer Dominick Pezzulo, demanded that her husband's death be edited in the final version of the film. Jay Hernandez portrays the late Dominick Pezzulo, who died in the collapse of the World Trade Center towers.
Although not emphasized in the film, McLoughlin and Jimeno were in extremely precarious health after their rescue and slipped into critical states multiple times during their stay in the hospital. Both men had to retire from the Port Authority on disability. They were still undergoing surgery for their injuries at the time the film was released.