Inventions - S3-E22
Visible crew/equipment: At the site of the major chemical leak, after Johnny falls from the pipes and Roy lifts him up, a couple of shots later there is a medium shot of one of 105's guys on Deluge 105 pumping out water, and we can see a cameraman (filming Deluge 105's closeups that we see during this scene) holding a handheld on the right of the screen, behind the pillar.
Inventions - S3-E22
Visible crew/equipment: After Roy and Johnny rescue the worker in the midst of the chemical leak, when Captain Stanley asks the Chief over the HT to send the ambulance, two crew members are seen behind him. When the victim is pulled across the lifeline, as he reaches the engine a crew member, with black hair wearing a white shirt, is seen standing behind the engine. Then, when Johnny hauls himself across the lifeline, just as he reaches the engine we see a crew member, with black hair wearing a white shirt (likely same one as earlier), who arches up then ducks back down behind the engine.
Inventions - S3-E22
Visible crew/equipment: On site at the major chemical leak, when Johnny burns his hand and falls backward, on the ground behind him there's a crew member that can be seen crouching behind stacked cement bags, looking in Johnny's direction.
Inventions - S3-E22
Visible crew/equipment: When Roy and Dixie are talking at the nurses' station about the "radioactive" truck driver, Johnny walks up to them, and when he removes the rope and stanchion, the actor's tape mark is visible at Johnny's feet.
Inventions - S3-E22
Visible crew/equipment: On site at the chemical leak, when Captain Stanley talks into his handie-talkie and says "Engine 36, we're not doing any good with this, let's try light water," in the next shot, while the camera pans to the right, we can see a cameraman (filming Deluge 105's closeups that we see during this scene) holding his handheld, standing in front of an engine and facing Deluge 105, just before the camera focuses on the guys with the hoses.
Inventions - S3-E22
Other mistake: When Station 51 responds to the incident of the man who fell through the ceiling at his mother's house, the footage of the squad and engine pulling up to the curb of the house is from episode 3x15, "Messin Around", when they rescue Old Bill after he's collapsed in his house.
Inventions - S3-E22
Other mistake: After Johnny and Roy are seen carrying the semi-conscious worker during the chemical leak, Captain Stanley tells Mike to get the life gun, and tells Chet to secure a lifeline, then before he mentions getting the guys from the catwalk via the lifeline, we hear Captain Stanley tell the Battalion Chief (into his handie-talkie), "Battalion 14, Engine 41," even though he's Engine 51, not 41. Additionally, when Cap tells Chet about the lifeline, two firemen behind Chet are wearing helmets with no company numbers on them.
Inventions - S3-E22
Continuity mistake: When Early and Morton are talking to the cab driver, in the overhead shot there's a hat on the desk, but in the shots facing Early the hat vanishes and other things on the desk rearrange themselves.
Inventions - S3-E22
Continuity mistake: When Chet's wearing his suction cup shoes, John uses the hose to wet the area around Chet's shoes, and then places the hose down on the ground, but in the shot from inside the van John's still holding that hose.
Inventions - S3-E22
Continuity mistake: When Station 51 is on site at the major chemical leak, Roy and Johnny are wearing SCBA tanks that have distinctive markings/stickers, and their tanks change while they search, locate and rescue the worker.
Inventions - S3-E22
Character mistake: Dr. Brackett calls Dr. Early "Jim." In the show, Dr. Early's first name is "Joe."
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.