No job is more stressful, dangerous or exhilarating than those of the Firefighters, Rescue Squad and Paramedics of Chicago Firehouse 51. These are the courageous men and women who forge headfirst into danger when everyone else is running the other way. But the enormous responsibilities of the job also take a personal toll.
- Taylor Kinney and David Eigenberg also starred in Five (2011) (TV).
- The Self-Contained Breathing Apparatus (SCBAs) worn by the cast are Scott 4.5 Air-Pak 75s. This is one of the most popular brands and models of SCBA with fire departments across America for its durability, reliability, and ease of use. However, the masks worn by the cast members are unrealistic. They are nonfunctional and were made specifically for the series with the anti-fog interior facepiece and exterior voice amplifier removed, the lens elongated, and the regulator mounted at an odd angle to clearly show the actors' faces. These masks would fog badly if they were actually flowing air. Real SCBA masks are put on separately from the regulator, which is connected after the mask is on, and disconnected before the mask is removed. The air demand and exhalation valves make a loud noise when operating, and muffle the voice of the wearer.
- The diabetic tree chopper's hat says Toppel tree service. This is a reference to the show's Greens Foreman Debra Toppel.
- During filming of the plane crash rescue sequence, WGN, a Chicago TV station, was apparently unaware. When WGN's traffic chopper came upon the location, they believed that an actual crash had occurred and broke into their news broadcast to cover it. This went on for several minutes before it was brought to their attention that this was being done for a television show.
- The other firehouse being considered for closure in addition to Firehouse 51 is Firehouse 17 from Backdraft, NBC Universal's first foray into the Chicago Fire Department.