SAN FRANCISCO (AP) - San Francisco fire investigators are looking into whether welding work was to blame for a massive blaze that barreled through an apartment building construction site.
The fire Tuesday evening threatened nearby buildings, prompting evacuations and forcing officials to call in about half the city's on-duty firefighters.
Mayor Ed Lee says they were lucky the fire did not spread.
The exact cause of the fire is under investigation, but Fire Chief Joanne Hayes-White says they are looking into preliminary reports that workers were doing torch work at the site shortly before the fire was reported.
The five-alarm fire created a plume of black smoke that was visible for miles as about 150 firefighters were called in to contain it. Two firefighters suffered minor injuries.
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