Two waterfront restaurants were evacuated and one of Portland’s most heavily traveled streets closed for more than three hours Sunday afternoon after a fire broke out in a roof vent of a building at 72 Commercial St.

Portland Fire Chief Keith Gautreau said the building houses Flatbread Company, a harborfront restaurant that specializes in wood-fired pizzas made in clay ovens, and the Ri Ra Irish Pub and Restaurant.

Gautreau said both businesses had to close Sunday following the fire, which was concentrated in a roof line hood vent, and won’t be able to reopen until the owners meet with the city’s code enforcement officer on Monday to develop a repair plan. A portion of the roof had to be opened up and there was some water damage, but Gautreau said the building’s sprinkler system worked well to contain the fire.

Gautreau said the fire proved to be stubborn, taking crews several hours to control hot spots. That forced him to call for the closure of one block of Commercial Street near the Casco Bay Ferry Terminal. The timing of the fire and street closure could not have been worse as the Old Port restaurants, bars and shops that line Commercial Street are flooded with visitors in July during  the height of the city’s summer tourist season.

“I stand behind my decision (to close the street),” Gautreau said Sunday. “I can’t be worried about the tourists. I have to worry about my firefighters and their safety.”

With temperatures soaring into the 90s in Portland, Gautreau said an ambulance crew evaluated two firefighters for possible heat exhaustion. They did not have to be taken to the hospital.

Gautreau said he was proud of his firefighters for attacking the fire and persisting.

“They were very hot and very tired, but we wanted to make sure the fire was out,” the chief said.

Sgt. Chris Mitchell of the Portland Police Department said traffic was diverted starting at 1 p.m. Commercial Street reopened around 4:30 p.m.