It's been a point of controversy for more than a decade. Now, researchers from the University of Alaska Fairbanks are weighing in.

World Trade Center Building 7 was not struck by a plane, but collapsed hours after the twin towers on Sept. 11, 2001. A draft report released this week by researchers at UAF suggests that the fall was not a result of fires, despite the findings of the National Institute for Standards and Technology, an agency of the U.S. Department of Commerce, in 2008.

The study was paid for by a group called Architects and Engineers for 9/11 Truth. The nonprofit is said to represent over 3,000 architects and engineers who have signed a petition calling on Congress to launch a new investigation into the destruction of the towers.

Dr. Leroy Hulsey, a civil engineering professor at UAF, led the four-year study. According to the Institute of Northern Engineering's website, the objective was to examine the structural response of WTC 7 to fire loads that may have occurred that day, rule out scenarios that couldn't have caused its collapse and identify types of failures that may have caused the fall.

The UAF team's findings contradict those of the 2008 NIST report, which concluded that WTC 7 was the first tall building ever to collapse primarily due to fire.

According to the NIST report, debris from the north WTC tower (WTC 1) ignited fires on at least 10 floors in WTC 7. Fires on some of the lower floors burned out of control. NIST said the automatic sprinkler system on those floors failed, causing the fires to spread.

"The primary and backup water supply to the sprinkler systems for the lower floors relied on the city's water supply, whose lines were damaged by the collapse of WTC 1 and WTC 2," a fact-sheet on the NIST investigation said. "These uncontrolled lower-floor fires eventually spread to the northeast part of WTC 7, where the building's collapse began."

Despite NIST's findings, critics of the government's account have long argued the building fell in a controlled demolition.

"We virtually simulated the building and we looked at that analysis and we also virtually simulated what they did, we couldn't get it to do what they did," Hulsey said.

Ted Walter, the director of strategy for the group, says one of its supporters approached Dr. Hulsey about the research partly because of UAF's reputation.

"When we started talking to Dr. Hulsey, it became very clear that the engineering program at the University of Alaska Fairbanks was very strong," Walter said. "And Dr. Hulsey was the chair of the department and he had a lot of experience in modeling structures and doing forensic investigations and so we thought it was a perfect opportunity for us to move forward."

Walter says the project budget, $316,153, also covered the time that Hulsey and the research team spent on the study.

The draft report is now open for a two-month public comment period. The final report will be published later this year; however, the research team plans to make all of the data used and generated during the study public by the end of September.

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