About 100 firefighters responded Wednesday morning to what the FDNY called an equipment fire likely sparked by welding on the 88th floor of 1 World Trade Center, officials said.



Fire officials said a civilian called the department just before 7:45 a.m. to report smoke billowing from an upper floor of the recently completed tower. As a precaution, the FDNY issued a call for all hands on deck and 100 firefighters responded, FDNY Battalion Chief Kevin Brennan said.



The FDNY said responding firefighters encountered workers welding, which was causing the smoke visible from outside the building.



There were conflicting reports from the Fire Department and the Port Authority about whether there had been a fire.



Authorities shut down some streets, including Vesey Street and the area west of Greenwich Street, to assist the investigation. All street closures had been lifted by 9:30 a.m.



Last week, a steel beam signed by President Barack Obama was lifted into place at the top of the 104-story skyscraper that's being built to replace the twin towers destroyed in the Sept. 11 attacks.



It's expected to be completed in 2014.

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