Updated 01/31/12 – 9:50 p.m.

CHICAGO (CBS) — A landmark building in the Gresham neighborhood was being torn down Tuesday night, after part of the building collapsed earlier in the day, injuring four people.

As CBS 2’s Suzanne Le Mignot reports, the top of a three-story building at 79th and Halsted streets collapsed along the roofline, sending the façade tumbling onto the pavement below at about 12:30 p.m.

LISTEN: WBBM Newsradio’s Steve Miller reports

Fire Commissioner Robert Hoff said four people were taken to area hospitals in serious condition. Their injuries were not life-threatening.

Carl Dean, who works for a nearby school, said he was walking under the scaffolding around the building when he was flung to the ground.

“We walked under the scaffold. Next thing I know, it fell on us,” Dean said. “I heard just a little crackling noise, you know, like pebbles falling onto the tin roof. Before you know it, the whole thing came down. I was trapped under it.”

halsted bulding collapse Gresham Building To Be Torn Down After Partial Collapse Hurts 4

Debris along the street following a building collapse that injured four people. (Credit: Steve Miller/WBBM Newsradio)

Photos from the scene showed the commercial and office building standing with its roof crumbled off, and piles of bricks on the ground. Among the bricks and heavy terracotta was the scaffolding that surrounded the building, leaving sheets of corrugated metal littering the sidewalk.

As CBS 2’s Pamela Jones reports, crews started using a crane to bring large pieces of the upper floors down and demolish the building Tuesday night. They were working cautiously around a utility pole that stands close by.

The landmark building was constructed in the 1880’s. It is currently owned by the city. Once a jewel of the neighborhood, it has been vacant for the past 20 years.

Hoff said the recent weather conditions and the age of the building played a role in the collapse, which he said gave way after years of neglect.

“When you see a tree growing through the roof of a building, that means the roof structure is deteriorated and, through the winters, it’s probably gotten frost and cold in there and it’s eaten away at the mortar and that’s why it’s loosened that fascia and that terracotta on the front,” Hoff said.

Shortly after the collapse, as a precaution, emergency crews were using heavy equipment to sift through the rubble, looking for a possible fifth person who might have been caught in the collapse, but no fifth victim was found and officials stressed that reports of that fifth victim being trapped were unconfirmed.

Xenia Powell, who witnessed the collapse, said two of her co-workers were among the injured.

“Watching the debris, trying to get the people out of the street, there was a lady walking and I just turned my head – me and my co-worker at the same time turned – and we saw two of our co-workers just laying in the street,” she said. “After that, I don’t know what happened. We just took off running to them to make sure that they were okay.”

Witnesses said a number of people risked their own safety to help dig out total strangers trapped in the rubble.

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