Rather, they suggest that a series of building code violations  and perhaps firefighting problems, as well  led to the tragedy. Construction workers’ removal of a section of the building’s standpipe left firefighters without water on the upper floors, and local fire companies failed to conduct regular inspections of the building  although it is unclear whether inspectors would have noticed the broken standpipe in a maze of pipes in the building’s basement, or if they simply would have checked to see the standpipe in place in the stairwells.

It has been known from the day of the fire that the struggle to get water on the flames was great. But few understood just how long that struggle lasted  now pinpointed by investigators at more than an hour, an eternity in the dangerous, fast-moving conditions of a high-rise fire.

In encountering the many hazards at the building, investigators found, firefighters improvised in their response and broke rules. They pushed their emergency air packs beyond the 45-minute limit in providing oxygen; they removed their face pieces in an effort to save air; they ignored warnings of being in danger; one firefighter rode atop a construction elevator.

Firefighter Beddia was overcome by smoke. After his colleagues pulled him from a spot near Stairway B on the 14th floor, his air pack was found to still hold 800 pounds per square inch of compressed air  or about five to eight minutes’ worth of air, considering that a full tank has 4,500 pounds per square inch.

Investigators have surmised that Firefighter Beddia must have removed his face piece and pushed the manual shut-off switch of his air pack before he became unconscious.

Investigators could not say why Firefighter Beddia removed his face piece.

In describing some of the risky tactics employed by firefighters at the scene, the investigators were careful to qualify their criticism, saying that the culture of the department was rich with a kind of “can-do” attitude, according to people who are aware of the findings.

Francis X. Gribbon, the Fire Department’s chief spokesman, said the department had been scheduling time this week to brief the families of Firefighters Graffagnino and Beddia, as well as the firefighters involved in the fire, about the inquiry’s findings. He said the department would not comment publicly on the findings until the families had been briefed.