Firefighters on Thursday responded to the third fire in a month on the north side of the city. The early evening fire at 66 Harris St. forced the occupants to flee and destroyed much of the basement garage and scorched the siding above the garage door. "The guys arrived on scene and saw the fire showing from the garage door," said Fire Chief Stephen Meranti. "They were able to access it very easily and contain it to the garage. ... We have smoke damage throughout the building but it's not major." The garage incurred significant damage to the materials stored inside and to the wiring. "The Sheetrock — the envelope you build for the garage — kept it in the garage area," he said. "So the building code works in separating the garage from the rest of the house." The blaze extended up the south side of the single-family cape, scorching and melting the siding but not affecting the structure. Meranti said it was not yet clear what had caused the fire and that the family would not be allowed back in that night. He said they had a place to go. The incoming shift was called in to assist and the top part of Harris at the North Street intersection was closed off to traffic. The fire had been contained and firefighters were sifting through scene by 7:30 p.m.