A ... new report into the collapse of World Trade Centre Tower 7 is set to fuel the fires of conspiracy as it suggests multiple blazes caused its downfall. The building, which was situated next to New York's Twin Towers, crumbled after the planes hit the towers. Conspiracy theorists have long suggested controlled explosions" were carried out in the building - but the official version of events says flaming debris from the burning Twin Towers flew into the 47-floor skyscraper. Tower 7, which housed the Secret Service, the CIA, the Department of Defence and the Office of Emergency Management, collapsed after seven hours of burning. The National Institute of Standards and Technology insists it was the first and only steel skyscraper in the world to collapse as a result of fire. But new ... claims suggest "office fires" could not have caused its destruction. The report, by a group of top engineers from the University of Alaska, insists the flames could not have brought the tower down. Dr J Leroy Hulsey revealed the team's ... findings at the Justice In Focus Symposium in New York. He said: "It is our preliminary conclusions based upon our work to date that fire did not produce the failure at this particular building." Historically, skyscrapers have resisted collapse after fires. A skyscraper in Philadelphia burned for 18 hours in 1991 and a high-rise in Madrid in 2005 each remained standing following fires.