Fire officials are investigating why a Denver high-rise fire didn't automatically sound building alarms and return elevators to the lobby as designed Wednesday.
"The smoke alarms, there's heavy smoke everywhere, it should have triggered the alarm automatically," said Denver fire spokesman Lt. Phil Champagne.
Eventually a resident in the 2000 Cheesman East condominium tower pulled a manual hallway alarm so hard it broke, and some people told 7NEWS said they eventually heard the alarm.
Yet, Champagne said, "We got a lot of complaints from the residents, saying they didnt hear any alarm."
Firefighters carrying gear up stairs to the blaze on the 25th floor, because elevators malfunctioned, also said there was no audible alarm, he added.
However, building managers maintained the fire alarm sounded, Champagne said.
"If somebody pulled a pull-box and that was the only way to activate the alarm, then that was a problem with that system," Champagne said.
A building manager declined to talk to 7NEWS.
A firefighter suffered heat stroke after climbing 24 flights to help put out the fire near the top of the 26-floor building.
No other injuries were reported.
The firefighter needed help walking down the stairs and was transported to a nearby hospital were he was recovering Wednesday afternoon, Champagne said.
The fire broke out about 11:11 a.m. at the high-rise, located at 12th Avenue and Race Street, one block east of the 12th Avenue Cheesman Park entrance.
It burned a condo unit on the 25th floor, Champagne said. The other unit on the floor had heavy smoke damage.
Neither was occupied at the time.
The owner of the condo, Joe Paine, told 7NEWS he has no idea what caused the fire. He said he had not put up his Christmas decorations yet and the only thing he did this morning before he left to run errands was make a cup of coffee. When he came back, his home was on fire.
"I've never come home to anything like that, so you don't have any feeling whatsoever. ... Nothing's really going through my mind other than the fact that I'd like to get up there and see just ... what has been ruined," Paine said. "Everything I have to take is up there, except what I have on, and that's not going to take me to the Debutant Ball."
Several residents said they didn't know there was a fire until a neighbor made his way up to the 25th floor unit, recognized the danger and pulled the manual fire alarm.
"One of the homeowners on the 26th floor called and warned us to the fact that there was a fire," said resident Terry Byers. "On the 25th floor, there was smoke pouring out of the door. The door was hot, so I didn't open the door.
"I just knew it was out of control, so I pulled the fire alarm," Byers said. "I started down the stairs telling everyone to get out of the building."
Condo resident Marilyn Harwood said, "A person in a building across the way was pointing at this building and started pointing up. So, I just dropped all my stuff and headed for the stairs"
"Really, I didn't hear anything," she said. "If I wouldn't have stepped outside, I wouldn't have known anything."
A woman visiting her daughter from out of town said she looked on the patio, saw tiny pieces of glass raining down, and knew something was wrong.
"The first thing she did was call down to the office and the office said we have to hurry there's a fire," said Marcia Hamilton, who lives on the 19th floor. "We looked up and we saw the billowing smoke. ... It was frightening."
"Stuck my head out on the balcony to see what was happening, and suddenly I saw ash and paint flecks, things floating around my head," said 15th floor resident Philip Van Hoevenberg.
Firefighters didn't immediately evacuate the building, but used a public announcement system to tell residents to "shelter in place" through the building, Champagne said.