After an investigation, fire officials determined that there was no fire inside the building, but that a small amount of rubbish had caught fire under a sidewalk grate on Fourth Avenue, Wright said. An air-intake vent for the building is directly above the sidewalk grate, and that caused the building to fill with smoke, Wright added.
Fourth Avenue was closed to traffic until about 4 p.m. because of the large number of fire trucks and other equipment that had been dispatched to the scene. The building was reopened after the small fire was put out, said Ken Hill, a maintenance supervisor for the building.
Hill called the Fire Department's response "exemplary."

