Reliving the nightmare

Six months ago, two brothers were filming a documentary in New York. It was about a probationary firefighter, an eager young man called Tony Benetatos. They had spent the whole of the summer filming the 21-year-old "probie" and, by September, had shot hundreds of hours of videotape about Tony and his colleagues.

What happened to Jules and Gedeon Naudet on the morning of 11 September will remain with them for the rest of their lives. That footage, most of which has not been seen before, forms part of a CBS documentary - called 9/11 after the date of the attacks - which was screened in the US last night.

For Tony and the two film-makers, 11 September began with a call around 8.30am to investigate a suspected gas leak at a crossroads less than a mile north of the World Trade Center. Jules went on the call. What happened next was seen on a thousand news bulletins last year: he heard a roar above him, turned his camera upward, and captured the only known video of the first plane striking Tower 1 of the World Trade Center.

The firefighters jumped in their truck and sped to the scene, arriving within minutes. They were among the first firefighters to reach the towers. Jules followed them in and filmed as they set up the command centre that co-ordinated the rescue of thousands of office workers from the North Tower.

As he filmed he could hear sounds outside. They were like distant gunshots, sometimes accompanied by smashing glass. Each one was a body striking the ground outside the World Trade Center; firefighters flinched at every impact.

"You don't see it but you know what it is," said Jules. "You know each time you hear that crashing sound a life has been extinguished. You can't get used to it."

Gedeon was at the firehouse when the first plane hit. With three firefighters he went to the World Trade Center and filmed the enfolding disaster from the outside. Despite the horrors they witnessed the Naudets shot no gory footage that day.

The film shows firefighters being ordered to climb the stairs to where the plane hit. Office workers, meanwhile, are seen leaving the building. Sometimes they are running. At one point a rumour sweeps the building that a third plane is on the way. A building worker methodically checks with a loudspeaker to see if people are trapped in the lift.

Jules was rushing to the escalators when Tower 2 collapsed. His video screen goes black, then records an unearthly snowstorm of debris.

Firefighters shouted at everyone to evacuate the building, and Jules followed a group of them as they searched for a way out. The building collapsed about six minutes later. Naudet fell to the ground behind a car, protected by a firefighter as dust and paper swirled all around him.

Both Jules and Gedeon thought the other died that day. That afternoon they had an emotional reunion back at the firehouse.

Amazingly, all the firefighters from Tony's company - Engine 7, Ladder 1 - also survived. Others did not. The documentary ends with pictures of the 343 firefighters who died that day, and an appeal for donations to a scholarship fund for their families.