The first victim's body doesn't land on the car after the explosion, but is there when firefighters arrive.
In the apartment fire, Stephen goes in to save a little boy. When there's an explosion, Brian falls back and his boots are all the way up, on another shot when he's on the floor his boots are folded down.
At the end of the movie the fire trucks exit the south facing doors of the fire house and we can see a setting sun in the western sky in the background. When they are filming from an aircraft, we can see the Chicago skyline with the first light of sunrise in the background. The only way you could view the Chicago skyline after sunset is from a boat on Lake Michigan. If it was evening in the view from the aircraft, there would be a lot more traffic on the roads. The scene was likely filmed early on a Sunday morning to minimize traffic disruption.
In the sewing company fire, the woman that was rescued (woman in green dress) can be seen in the crowd outside of the building as 17 is approaching the building.
In the last scene the trees have green summer leaves as the trucks exit the house. During the ride, they are passing trees that do not have leaves because it is winter.
From 0:05:09 -no professional firefighters would lay out their hoses in such a haphazard manner.
During the garment factory fire, a shot of the pump panel of Engine 17 is visible with no electrical lights on, no suction, no pressure and no discharge pressure. All the gauges are idled and the engine isn't even running during a working fire.
At 0:31:19 -a Firefighter is using a hand spray pump.
In the garment factory fire when Brian goes off searching for a person, there is a drain on the floor and you can see the fuel the crew spread on the floor, the camera then cuts to a different angle and when it returns the fuel is on fire.
That's how flammable liquids ignite. One second there's a puddle, then the vapors meet a flame and the puddle flashes in the next second.
"There is no need to break out the car windows in order to run hoses through. However, this was clearly done to get back at the owner of the expensive car who recklessly parked in front of the fire hydrant, whether it was necessary or not."
This actually is sometimes necessary, although firefighters will avoid it if possible. Because of the high water pressure in a fire hose it must not be kinked or even bent too sharply, or there is a possibility of damage to the pumping equipment or the hose itself. If a car is parked too close to a fire hydrant to safely pass the hose over it, the firemen may have no choice but to break the windows and pull the hose through. As tempted as they may be, the are very unlikely to do so merely out of spite.
This actually is sometimes necessary, although firefighters will avoid it if possible. Because of the high water pressure in a fire hose it must not be kinked or even bent too sharply, or there is a possibility of damage to the pumping equipment or the hose itself. If a car is parked too close to a fire hydrant to safely pass the hose over it, the firemen may have no choice but to break the windows and pull the hose through. As tempted as they may be, the are very unlikely to do so merely out of spite.
A mannequin cannot scream for help. But there is a real human also rescued from that fire, and the sounds of the fire are shown to have a screaming/gasping quality, either of which Brian could easily hear on his way to the mannequin.
The pressure dials on the fire truck at the garment factory all read zero.
In the final factory fire scene when Kurt Russell is wounded on the catwalk, the two firefighters who trying to get to Kurt are covered by William Baldwin spraying and soaking them with the water hose. One guy is wearing a hat and as the two reach Kurt, he takes off his hat and his hair is completely dry (as if he just got out of his dressing room). Though the hat would cover his hair from the water, he would still be sweating profusely due to the intense heat and wearing a heavy firefighters jacket.
Just as the department goes to a call when the hippies are around, you can see the overhead light-bar on while the fire bell rings.
Throughout the entire movie -the axes are obviously fake because their handles are made of a straight stick instead of being curved and shaped like real ax handles.
During the funeral procession Rimgale is not wearing a sling for his injured shoulder, but he has one at the cemetery.
The McCafferty bros. are supposed to be lifelong Chicagoans, yet neither one has anything close to a Chicago--or even Midwestern--accent at any point in the film.
At the end of the movie the driver of the ladder truck is shown smoking a cigarette in the truck. Smoking is expressly forbidden in any city vehicle.
When Brian and Jennifer are riding on the top of the fire truck, there clearly is no fire jacket present. But once the truck stops, Jennifer is wearing a fire jacket as Brian greets the firefighters.
A cobra street lamp is present in the 1971 scene. They were not in use back then.
During opening 1971 sequence, an 80's style Dodge Caravan can be seen parked on the street while the firefighters are in route to the fire.
In the 1971 scenes we can see buildings that are retrofitted with brown thermopane replacement windows. These types of windows were not comon until the early 1980s.
During the "you go, we go" sequence, lighting equipment is visible several times
The stunt mat that Shadow lands on after the explosion.
In the warehouse fire, when Bull is holding onto Axe and the explosion knocks them off the platform, you see Bull dangling from his "harness" and reaching for the beam in mid-air for a split second before the camera angle changes.
Reflected in the screen door after the "stinking spinach" line.
In the final fire when Brian is running to get to the side as the roof collapses in flame, a crew member can be seen running on the roof to the side of the building towards the left.
At 0:04:14 -the second thing the Fire Department does (after securing a water supply) is shut off the gas line.
No Fire Department (or other emergency service) offers a ride along to civilians during an emergency run.
From 0:25:16 -the explosions come from outside the building.
In the hospital scene you can see a boom mic in top left corner when McCaffrey brothers are arguing at around 1 hour 22 minutes 30 seconds.
Experienced firefighters would know better than to ride elevators in buildings where fires may or may not be in progress.
Throughout the movie, numerous firefighters are seen *not* wearing their air packs.
At 0:21:49 -the harness is twisted.
In the opening scenes, Dennis McCaffrey is wearing an officer's helmet that reads "Engine 17". But, going to the fire, he climbs into the officer's seat on the ladder truck. If he was wearing the Engine 17 helmet, his place would have been on the actual engine. To ride the ladder truck, his helmet would have read "Truck 46".