Two firefighters were killed yesterday battling a blaze in the Deutsche Bank skyscraper, a vacant relic of the Sept. 11 terrorist attack that was in the process of being dismantled.

The firefighters were among hundreds who poured into ground zero all afternoon to fight the high-rise fire, which was finally brought under control after seven hours. At least five others were hospitalized, but were expected to recover.

The building, at 130 Liberty Street, had stood as a ghost since parts of the twin towers crashed into it, leaving it severely damaged and filled with toxic debris, including asbestos, dioxin, lead and chromium. For residents nearby, the acrid smoke brought back memories of the grim dust clouds that lingered after the attacks.

The demolition work created difficulties for firefighters trying to reach and put out the blaze, which started on the 17th floor, allowing the fire to mushroom out of control, fire officials said. The building did not have a working standpipe, which runs through high-rise buildings to provide a source of water for firefighters.

It was “a truly difficult fire,” Fire Commissioner Nicholas Scoppetta said. “We had to lift lines from the street, with ropes in order to get it up to the 17th floor.”

Mayor Michael R. Bloomberg said the building was structurally sound and not in danger of collapsing. He also said preliminary air-quality tests showed an increase in particulate matter but no hazardous contaminants, though he warned that results of more complete tests would not be available until this morning.

“Air quality and the environmental impact, as you might imagine, are a top concern to us and we are monitoring the situation very closely,” the mayor said at a news conference last night.

All civilians working in the building got out unharmed when the fire was reported at 3:36 p.m. There were no evacuations of adjacent buildings, the mayor said.

Mary Costello, a spokeswoman for Bovis Lend Lease, the construction company in charge of the building’s dismantling, deferred all comments to the Fire Department.

The cause of the fire was under investigation, though officials ruled out acetylene torches, which were not in use Saturday by workers dismantling the building. Investigators are looking into whether the fire was started by a worker smoking, an official said.

The two firefighters became trapped in the building and died of what appeared to be cardiac arrest resulting from exposure to carbon monoxide, Mr. Bloomberg said. They were Joseph Graffagnino, 33, of Brooklyn, who had been with the department for eight years, and Robert Beddia, 53, of Staten Island. An official said he had been with the fire department 23 years and was the senior firefighter on the scene. They were taken to NYU Downtown Hospital, where they died.

They were assigned to Engine 24 and Ladder 5 of Battalion 2, which are housed together at Sixth Avenue and Houston Street. Eleven firefighters from that station house died on Sept. 11.

The two men were found on the 14th floor close to a hose line. An official said they ran out of air.

Mr. Scoppetta said the fire was discovered when workers at the site saw smoke and notified an elevator operator.

Paula Sanchez, who was cleaning on the 18th floor, said she smelled smoke and radioed Marshall Greenberg, the elevator operator. He picked her up, and they went to the 19th floor to get her backpack, then headed down.

But the elevator hesitated, and Mr. Greenberg switched it off and on to get it running again. “I thought I was a goner,” he said.

The workers made it out of the building and notified the Fire Department, which arrived within 3 ? minutes, Mr. Scoppetta said. Eighty-seven units and 475 firefighters responded, he said.

City, state and federal officials also rushed to the scene, some wearing protective masks over their mouths and noses.

Witnesses at the scene described one of the injured firefighters being pulled from the fire as about a dozen of his colleagues swarmed around and helped carry him into an ambulance.

“Give him air, give him air!” one firefighter yelled. It was unclear if the injured firefighter was one of the men who died.

Friends and neighbors gathered at Mr. Graffagnino’s parents’ home in Brooklyn last night, where they sat on the stairs outside.

“Everyone is in shock,” said one neighbor, who did not want to give her name. “It doesn’t get worse than this. He was the best father. The best husband. The best nephew there ever was.”

Another neighbor, Alexis Trapani, 41, said: “He was a baby when he moved here. He was the nicest person. He seemed so happy. He came from a very close-knit family.” She said she believed he had two children.

Officials said that in addition to the nonfunctioning standpipe, fighting the fire was made difficult by the asbestos removal, which created “maze-like conditions.”

Many areas were partitioned off with plastic, and hallways and walls one would find in other buildings had been torn out.

Workers told officials they had been stripping asbestos from beams, and the fire spread quickly through gaps and holes in the structure.

The blaze spread through spots on 10 different floors through those pockets and voids. It went as high as the 26th story, which is now the top floor of the building.

Demolition of the building, which once stood at 41 stories, had been delayed for years because of environmental concerns, labor and contract disputes, and to accommodate the search for human remains from the terrorist attacks. The chief medical examiner’s office said in February that 766 body parts had been found in the building. Most were fragments less than four inches long.

Demolition finally began in February, but because of the hazardous materials inside, the building had to be taken apart piece by piece, all of the work closely monitored by environmental officials. Workers had dismantled about 15 floors as of Tuesday.

Bonnie Bellow, a spokeswoman with the federal Environmental Protection Agency, said there was work being performed at the building yesterday, as on most Saturdays; a shift ended at 3:30 p.m., right around the time the Fire Department received the first reports of a fire at the building.

Ms. Bellow said there are 12 air-quality monitors installed in and around the building. “At this point, we’re gathering whatever results we can from these monitors,” Ms. Bellow added. “For some of the contaminants, we can get instant readings, but other contaminants require further analysis of the monitors’ readings at a laboratory.” She could not provide more specifics.

Burning debris flew from the building to the street below as dark plumes of smoke billowed over Lower Manhattan in a scene eerily reminiscent of the Sept. 11 terrorist attacks.

“The air smells bad,” said Catherine McVay Hughes, a member of Community Board 1 and chairwoman of its World Trade Center redevelopment committee, which has been monitoring the dismantling of the Deutsche Bank.

“The question we have right now is, what is it that caught fire at the Deutsche Bank? Was it the debris? Was it the boxes containing the asbestos?” asked Ms. McVay Hughes, who lives one block east of the site. “The community is devastated that this happened, and we want to know what will be done to prevent this from happening again.”

Mayor Bloomberg called the fire and the deaths of the firefighters “another cruel blow to our city and to the Fire Department, and specifically to the house that Engine 24, Ladder 5 and Battalion 2 are in.”

Some residents in the neighborhood surrounding ground zero said they weren’t surprised that a fire occurred at the black-draped building, given the problems that delayed its demolition for years.

Viktoria Baklanova, 40, a resident of 90 West St., a 24-floor residential building that overlooks ground zero on its north side, said that the fire evoked scary memories of Sept. 11, especially since firefighters died. “It’s very sad,” she said. “A lot of people died in the area. They just keep dying.”

They should have removed the building much faster, she said. “It just took too much time.”