Blocked stairwells, radio confusion, and misinformation about the water supply system thwarted firefighters’ efforts to put out a blaze at a toxic ground zero skyscraper that killed two firefighters, an internal report said today.

Fire officials released the 176-page report along with 40 pages of emergency radio transmissions from more than 100 firefighters who went into the former Deutsche Bank tower on Aug. 18, 2007.

Fire Commissioner Nicholas Scoppetta said the report “is not about affixing blame” and his department would conduct further inquiries about its performance before the fire.

But the report detailed a litany of problems fighting the fire that Mr. Scoppetta said would have been handled differently if officials had known of the hazards.

Firefighters were told at the scene by construction workers that a standpipe supplying water to fire hoses worked, wasting 20 minutes before realizing it was broken, according to the report. It took 13 minutes for workers to call the department, and another 67 minutes to get a water supply.

Firefighters sent more than 30 distress signals, including 14 maydays, from inside the burning bank tower, but some weren’t heard because they came in at the same time. Mr. Scoppetta blamed “a failure of radio discipline” and said firefighters would be trained to allow the urgent signals to come through one at a time, keeping channels clear once one signal is posted.

“Some messages were not being received. Everybody was speaking over them,” Mr. Scoppetta said.

There was no record of maydays or the less serious “urgent” radio transmissions sent from firefighters Robert Beddia and Joseph Graffagnino, who died of smoke inhalation, Mr. Scoppetta said.

The report didn’t explain why the fire department hadn’t inspected the tower, which was being cleaned of toxic waste and dismantled, in over a year. Several other agencies were assigned to inspect the tower daily; a Manhattan grand jury is considering whether to criminally charge contractors or the government agencies overseeing the project in the blaze.

“It was very, very important that the building had not been inspected, and we will deal with that,” Mr. Scoppetta said.

Careless smoking is believed to have started the fire, which began on the building’s 17th floor. Beddia and Graffagnino were found dead on the building’s 14th floor. Neither were wearing face masks connected to air tanks, and Beddia’s tank had about five minutes left of compressed air inside it, the report said.

Mr. Scoppetta said Beddia was probably trying to conserve air while he continued to fight the fire, “and probably thought he still had enough to get to the perimeter and get out.”