BOSTON — Fire destroyed a landmark seafood business on the waterfront early Friday, snarling rush hour traffic. There were no reports of injuries.

The cause of the blaze at James Hook & Co. was unclear. The wholesale and retail company extends on pilings over the harbor.

Firefighters struggled to contain the blaze several hours after it broke out about 3:30 a.m. Flames burned through rooms full of corrugated cardboard boxes used for shipping seafood, fire department spokesman Steve MacDonald said.

They battled the fire from outside the wooden building out of fear it would collapse. Divers were in the harbor to check the integrity of the pilings below the building to ensure the pier was safe. They also had hoses in the water to keep fire from threatening a nearby wooden pedestrian bridge, MacDonald said.

No one was in the building when the fire began. Fire Chief Kevin MacCurtain said damage was estimated at $5 million, including the loss of about 60,000 pounds of lobster.

"When you've been coming to the same place for 30 years and opening up every morning and suddenly you can't service your customers anymore, it's a strange feeling," said one of the owners, Ed Hook.

He said he received a call from his brother, Jimmy, around 4 a.m. that their business was burning. The company is now run by third and fourth generations of their family.

"I didn't know how to react. I was in shock. He said there was a fire and it was bad, so I got in my car and headed over," Ed Hook said. "It hit me when I got here."

James Hook & Co. has been in business since 1925, when the Hook brothers started trucking their catch of lobsters from Maine and Canada to Boston's fish piers and selling them directly to the city's top restaurants. The business now ships 50,000 pounds of lobster a day, according to its Web site.

The building sits in the heart of Boston's waterfront, close to the luxury Boston Harbor and Intercontinental hotels and a Coast Guard facility. It is across the street from fire department headquarters and the city's financial district.

A portion of Atlantic Avenue, the main thoroughfare along the waterfront, was shut down and an Interstate 93 exit closed.

Meanwhile, firefighters in New York continued to battle a stubborn blaze that broke out Thursday evening at the F.X. Matt brewery in Utica.

The fire erupted just as a weekly outdoor concert hosted by the company was starting. Concert-goers were evacuated. Hundreds of nearby residents were told to leave their homes.

Brewery officials said the fire started in a brick building where the Saranac brand is canned and processed. Two employees of the 120-year-old company were treated for smoke inhalation, they said.

The cause of the fire was under investigation.