With false alarms commonplace at the Hi View Gardens apartment complex in McKeesport, some tenants' first reaction as dawn broke yesterday was to shrug off the shrieking smoke detectors.

Keith Weston, 25, who was just turning in, thought it was another prank. Then came police officers and firefighters pounding on doors at 520 Coursin St., ordering tenants to evacuate the three-story building's 27 units.

"As I lay down, I heard them say, 'Get out of your apartment! The building's on fire!" said Mr. Weston, who hustled out of his first-floor home without even grabbing his wallet.

A fast-moving blaze was tearing through the brick building, channeling thick, dark smoke into stairwells and forcing tenants to huddle at second- and third-floor windows awaiting rescue.

Help came quickly as upward of 50 firefighters from eight companies swarmed to the apartment complex at Coursin Street and Sixth Avenue, near McKeesport's main drag.

Even with their efforts, seven adults and children were treated at UPMC McKeesport, mostly for smoke-related problems, and two firefighters suffered minor injuries.

Fire Capt. Bruce Drye Sr. estimated that firefighters rescued about two dozen people by pulling them through windows and carrying them down ladders.

"I've been here 28 years, and the most I've ever evacuated is like three or four," Capt. Drye said at the fire station, several hours after the fire was quenched.

Several feet away from him, firefighters watched their exploits on the noon TV news, picking themselves out at the scene as the video rolled. Capt. Drye's son, Bruce Jr., recognized himself carrying someone down a ladder. He said a civilian kept handing him children through a window.

That civilian was Tomez Faulkner, 21, of Penn Hills who had been staying with his girlfriend, Lindsey Jackson.

Standing outside the building, Mr. Faulkner wore a soot-stained T-shirt that had once been white.

Mr. Faulkner said he and his girlfriend fled from her third-floor apartment and headed downstairs, but when he got outside he turned around and realized she hadn't followed him after all.

He raced back upstairs. The smoke became too thick to descend again, so he joined a group of adults and children seeking fresh air at a window in the middle of the hallway and waited until a ladder truck arrived.

Firefighters got the call at 5:59 a.m. and had the blaze under control by 7:52 a.m. Capt. Drye knew immediately that the blaze was so intense his efforts needed to focus on rescuing people, not putting out the fire.

"The fire was so fast, it grew so fast, we couldn't fight the fire," Capt. Drye said. "Our main concern was saving lives."

Capt. Drye said the fire began in a second-floor bedroom, but he did not have further information. The Allegheny County fire marshal's office is investigating and did not return a call seeking comment.

Joan Zugai, community manager for AIMCO, the apartment management company, said about 50 residents were displaced. She was working on finding housing for eight people who were not being housed by family or the American Red Cross. It was not clear how extensively the building was damaged.

In a parking lot across the street, Hollie Davis, 22, sheltered her three children in a minivan belonging to her fiance's mother. Three-month-old Jacob dozed with a bottle and his 2-year-old brother, Jordan, tore into a bag of cookies.

Ms. Davis said she was asleep when her 11-year-old nephew -- one of two nephews spending the night -- woke her up. She hustled everyone out.

"I didn't even have bottles for my baby," Ms. Davis said. "The smoke just came fast through the whole building."

She borrowed clothes for her children and relied on others' kindness for bottles and diapers.

"It was definitely scary," she said. "You just don't know what's going on, you just don't know what's going to happen. You don't know what you're going to go back to."

The Red Cross will also meet with other apartment residents not present at the time of the fire if help is needed. Those residents can call 1-888-217-9599.