The City Council of Orlando, Florida, was only too happy to let the production blow up their old ugly City Hall, with producer Joel Silver paying $165,000 for the privilege. The domed building behind it, with the Coca-Cola sign mounted on it (stage dressing; it was removed afterward), is Orlando's NEW City Hall, which had just opened. In the widescreen shot as Riggs and Murtaugh enter the building, on the right side, the SunTrust (then SunBank) Center, to this day Orlando's tallest building, is plainly shown. Another shot shows the distinctive cylindrical Orlando Utilities Commission building.
During the scene where Riggs and Lorna are comparing scars, many of Riggs' were given to him during the events of Lethal Weapon 2 (1989), specifically the gun shots in his lung and the knife wound in the back of his leg..
Following the film's massive box office success, Warner Brothers planned to give Mel Gibson, producer Joel Silver, and director Richard Donner brand-new black Range Rovers as thank-you presents. However, WB Chairmen Bob Daly and Terry Semel only told Donner that they were invited to a celebratory lunch (the Range Rovers were going to be a surprise gift) and Donner wanted to invite Danny Glover, Joe Pesci, Rene Russo, and writer Jeffrey Boam to join them. So the studio simply raced around Los Angeles and kept buying one new Range Rover for each new lunch guest, and presented them to the entire happily stunned group when the meal was over.
For the film's spectacular climax, the filmmakers found an abandoned housing tract just outside of Lancaster, California. A victim of the Savings & Loan crisis, the property had been untouched for over two years. 12 out of the 56 houses in the tract became a dramatic inferno for the scene. To meet EPA standards, each house had to be stripped of all insulation, paper, wiring, plumbing, and anything plastic. In addition to administering a heavy dose of flame retardant to each house, propane gas lines were used in each of the 12 houses. This allowed the creation of a fire that would not burn wood and one that could be lit and re-lit as needed for each take. Oddly enough, the fire sequences proved to be a welcome heat source during the night shooting, as it took place in January, where the desert temperatures dipped down to as low as 11 degrees Fahrenheit.
A scene which was cut from the Theatrical cut of this movie, but restored in the Director's cut was a scene that took place between the scene where Riggs and Lorna compare scars/wounds and the scene where Riggs finds Murtaugh out on his boat. It shows Riggs at his beachside trailer (which appears to be undergoing some kind of renovation) on his couch watching a Three Stooges movie with both Sam and the dog from the Warehouse. The contractor McGee (who worked on Murtaugh's hobby room in Lethal Weapon 2 (1989)) also appears in the scene as the contractor performing the renovations to Riggs' trailer. Later in the scene, Rianne drives over to the trailer and tells Riggs of her concerns about Murtaugh not coming home that previous night.
Director Richard Donner is an animal-rights and pro-choice activist, and placed many posters and stickers for these causes in the film. Of note are the T-shirt worn by one of Murtaugh's daughters (the actress's idea), an 18-wheeler with an anti-fur slogan on the side, and a sticker on a locker in the police station. See also trivia for Conspiracy Theory (1997).
For promotion of the film, theater lobbies featured a 3-D cut out of the movie poster of Riggs and Murtaugh posing with their guns and Leo Getz peeking from the background. On the display, the was a motor which helped Leo's head bob up and down from behind them.
During the armored-car chase, Delores, the excitable driver of the armored car chasing after Riggs (Mel Gibson), refers to herself as a "Road Warrior." The Road Warrior character (a.k.a. 'Mad' Max from Mad Max (1979) and Mad Max 2: The Road Warrior (1981) as well as follow-ups) is the role that made Gibson famous to North American audiences.
After receiving the unusual writing credits (Story by Jeffrey Boam, Screenplay by Jeffrey Boam and Jeffrey Boam & Robert Mark Kamen), the advertising department assumed it was a misprint and produced posters with the credits "Story by Jeffrey Boam, Screenplay by Jeffrey Boam and Robert Mark Kamen". After a few of the posters had been sent out, the WGA contacted the department, telling them that the initial credits were the correct ones, and ordering the posters to be recalled and destroyed. A few still remain in circulation, however.
After the building explosion, when they are busted down to patrolman, Riggs and Murtaugh argue over which wire Riggs cut, having forgotten which wire he cut. During the incident, Riggs swapped which wire he was going to cut, first saying blue, then switching in the middle to red. In the cropped pan-and-scan TV version, it is unclear which wire he eventually cuts. However, in the original widescreen theatrical version, it is clear that Riggs cuts the red wire.
The housing construction site was not a set built for the film but an actual real estate project near Lancaster, California. The developers went broke before the homes could be completed. The production company could film there only after agreeing to tear the site down completely after the shoot.
The family looking at the Murtaugh's home are seen driving away in a GMC Typhoon. The Typhoon used (painted Aspen Blue with a gray cloth interior) was a 1991 model which was one of 4 that exist in the world, produced as prototypes prior to its official production run for the 1992 model year. It is rumored to be stored in a private vehicle collection with roughly 500 miles on the odometer in Lansing, Michigan.
The computer game seen on Lorna Cole's (Rene Russo) computer is called "The Three Stooges" by Activision and Cinemaware. Martin Riggs is an avid fan of The Three Stooges. Her computer is therefore an Amiga 500 or 2000.
The trivia item below may give away important plot points.
This is the only movie in the series in which Riggs and Murtaugh manage to make an arrest, not counting the suspects Riggs arrests in the first film before they became partners. Unfortunately the suspect they arrested, Billy, is still killed before he can make it to trial.