UPDATED 12/22/10 9:52 p.m.

CHICAGO (CBS/WBBM) — Chicago Mayor Richard M. Daley tearfully remembered one of two Chicago firefighters killed in the line of duty as someone who always wanted to talk about the fire department.

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Daley said at a Wednesday news conference that he knew Corey Ankum and his family well. Ankum’s wife is Daley’s personal secretary.

Daley called his secretary “a true friend and a confidante.” Daley says Ankum loved to talk about being a firefighter.

Ankum, 34, and Edward Stringer, 47, were killed in the fire at an abandoned South Side building when the roof collapsed.

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At least 17 other firefighters were injured, some of them critically.

An emotional Daley ended his remarks by saying, “God Bless” the members of the Chicago Fire Department.

As CBS 2’s Mike Puccinelli reports, the two firefighters were pronounced dead after being rescued from the fire at the vacant Banner Dry Cleaners, 1744 E. 75th St. Thus, what should be a festive time just three days before Christmas has instead become a time of mourning and tragedy.

At a news conference Wednesday afternoon, Fire Commissioner Robert Hoff identified the firefighters who died as Corey Ankum, who had been on the job less than two years and was assigned to Tower Ladder 34, and Edward Stringer, who had been in on the job 12 years and was assigned to Engine Company 63, detailed to Truck 16.

At Ankum’s fire station Wednesday, fellow firefighters told CBS 2’s Suzanne Le Mignot that a fund has been set up in Ankum’s honor, to help his wife and three children in this difficult time.

The “Firefighter Corey Ankum Memorial Fund” is set up through Chase Bank, and donations are being accepted at Chase locations.

One firefighter was dead on arrival at Northwestern Memorial Hospital, another at Advocate Christ Medical Center in Oak Lawn. The Cook County Medical Examiner’s office confirms the fatalities.

Fire department officials say both Ankum and Stringer died from trauma injuries suffered in the collapse.

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A total of 17 more firefighters were injured. As of 1:30 p.m., a lieutenant remained in stable condition at Northwestern, Hoff said.

The fire broke out about 7 a.m., fire Media Affairs spokesman Will Knight said.

By 7:24 a.m., the alarm had been elevated to a 3-11 alarm and an EMS Plan 2, which automatically sends at least 10 ambulances to the scene, had been placed into effect, Knight said.

Four Chicago firefighters were pulled from the building after being trapped when the roof and wall collapsed. Two did not survive.

The building had a flat roof in the front and and a bow-string truss roof in the back. While truss roofs often pose a danger of collapsing during fires, Hoff said fire crews decided to enter the building for a precautionary search because the fire was in an office area well below the ceiling.

“When you find an open door in the rear of the building, again, in this weather, we can go into any building somehwere and find someone inside taking refuge,” Hoff said.

A “mayday” call was issued during the blaze, as four firefighters were missing for a period of time. A rescue crew moved in swiftly, and all the firefighters were eventually accounted for, officials said.

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But the fire still ended in tragedy.

With the two firefighters’ deaths, the fire Wednesday became the deadliest fire of the year for the Chicago Fire Department.

Witnesses Describe The Horror

A few hours after the fire, there was commotion at the scene. A sister of one of the injured firefighters raced up, seeking to find out the hospital where her brother had been taken.

Kimberly Lofton saw the roof and wall cave in.

“I just saw the firemen as they were getting off the ladder; they were sucked on in,” Lofton said, “and the next thing I know, the firemen were saying, ‘Help! They need help, because it caved in! It caved in!’”

Lofton said when firefighters realized that four of the brothers were trapped, the scene became frantic.

“’They’re trapped! They’re trapped! They’re trapped in there!’ By that time, all of them were working to try to get them out of there,” she said.

Multiple ambulances responded to transfer the injured to area hospitals. Other firefighters – their emotions raw – rushed to help out any way they could. Conditions at the scene were perilous.

Lofton watched as injured firefighters were taken away one by one. She says she’ll never forget what she saw.

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“They disappeared. They just went on down,” Lofton said. “I saw, I think, three of them.”

Jezell Taylor who works at the car wash next door said he was shocked to see the fire. He said the commercial building has been abandoned for about 15 to 20 years, and homeless people would find shelter there at night and at times start a small fire to keep warm.

Friends and family of loved ones stopped by to look for firefighters. Many of them walked around frantically, while on the phone.

Doreen Weiher came by to support the firefighters on behalf of her husband who died in 1998. She said her husband, a Chicago firefighter, died off-duty and this is what he would have wanted her to do.

“It’s so sad, because I could feel the family’s pain and the firefighters’ loss. There are no words for it period,” she said.

Two firefighters were taken to Northwestern Memorial, three to Advocate Christ, four to the University of Chicago Medical Center, and one to St. Bernard Hospital and Health Care Center, officials said. It is not known where the other six were taken.

A Somber Scene At The Hospitals

At Northwestern Memorial, CBS 2’s Dana Kozlov reports there was a somber tone in the emergency room all morning. In addition to the firefighter who died there, another, identified as Bob Kawa, was in the intensive care unit with a burned esophagus.

The president of the Firefighters’ Union was seen rushing into the emergency room. Dozens of firefighters were present at the hospital, as well as police officers — including the deputy police superintendent.

Firefighters — some of them very emotional — were arriving all morning. For a while, police had Erie Street blocked off near the emergency room entrance.

Meanwhile, a procession left Advocate Christ with the other fallen firefighter’s body in a single ambulance.

At a news conference, Chicago Firefighters Union Local 2 President Tom Ryan offered consolation to the families of the two firefighters who lost their lives.

“Our thoughts and prayers go out to the families of all firefighters today,” he said. “No matter how well you’re prepared, no matter how much experience you have, a morning like this is just something that takes you by surprise.”

But Ryan said the families can take solace in “knowing that their husbands, their fathers, their brothers, are herores.”

Investigation Is Underway

As CBS 2’s Susanna Song reports, the cause of the fire is unknown. The Chicago Fire Commissioner will only say that a full investigation is underway. He also said there was no indication that the roof was unstable before crews went inside.

“We’re investigating what caused that heavy roof to collapse,” said Commissioner Hoff. “We can only put a theory out there that, because the fire wasn’t that well-involved in that area, it was more in an office area in the back, that maybe the snow and ice…there’s many things that could contribute, age of the building.”

Fire officials say the crew went inside looking for suspected homeless people. Workers at the car wash next door said even though the building was empty for years, squatters spent the night there, often starting a small fire to stay warm.

Hoff says firefighters followed procedure and defends the decision to go into the building – despite the dangerous truss roof in the back.

“This building had no indication to the chief officer in the company or officers on the scene that it was in danger of collapse,” said Hoff. “And that’s when we make our decision to go in and do a search.”

But was it the right decision?

“No comment on that at all,” said Tom Ryan. “I will not second-guess anybody.”

“Every firefighter that was there did their best they could to save their brothers,” said Hoff.

Building department officials confirm there have been a history of violations at the building where the fire occurred, dating back to 2007. The owner had been to court several times. But, according to a building department spokesman, on most recent inspection, it was deemed secure. Sadly, that was not the case for the two firefighters that lost their lives.

In all, 19 firefighters were taken to hospitals for treatment today. Five remain hospitalized and are expected to recover.

“The members that are injured, we have people staying with them 24/7. We have someone with their family members 24/7. We need to cope with their loss and take care of them first. We’ll pick up the pieces in house with ourselves,” said Fire Commissioner Hoff.

Grief counselors are being made available for the entire department. CBS 2 spoke to some firefighters tonight who say that’s helping them cope.

The last Chicago firefighter to die in the line of duty was Christopher Wheatley, who lost his life in August as he fought a fire at Avec Restaurant, 615 W. Randolph St. He fell off a ladder and plunged three stories to the ground.

The last time multiple firefighters were killed in a fire was on Feb. 11, 1998, when firefighters Patrick King and Anthony Lockhart died fighting a fire at Beverly Tire and Auto Service, 10611 S. Western Ave., Hoff said.

Wednesday also marks the 100th anniversary of the 1910 Union Stock Yards fire, in which 21 firefighters were killed.

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CBS 2’s Suzanne Le Mignot, Susanna Song, Dana Kozlov, Vince Gerasole and Mike Puccinelli, WBBM Newsradio 780’s Bernie Tafoya and Regine Schlesinger, and the Sun-Times Media Wire contributed to this report.