Several blocks in the Inner Harbor were closed to traffic briefly yesterday morning while firefighters extinguished a blaze at a six-story building at Light and Lombard streets.

The brick building at 28 Light St. is not occupied and is undergoing construction work, said Chief Kevin Cartwright, a Fire Department spokesman.

The fire appeared to be caused by a construction worker who was using a blowtorch to cut apart an air conditioning unit on the roof of the building about 10:30 a.m., Cartwright said.

Nobody was injured in the blaze, but Light Street was blocked off for about 45 minutes while the fire was being fought and salt was brought in to prevent water on the streets from freezing.

annie.linskey@baltsun.com