Update, 7:42 p.m.: Darren Denly, 25, has been arrested and accused a starting the Canal Street fire. Click here to read more.

Update, 2:25 p.m.: Firefighters remain on the scene of the Canal Street fire, searching for smoldering hot spots and completing the investigation in the cause of the fire.

The southbound lanes of Canal Street between N. Rampart and Burgundy remain closed. Street-car traffic on Canal was expected to reopen by 3 p.m.

Update, noon: The fire on Canal Street was deemed under control around 11:50 a.m., nearly eight and a half hours after it began, officials said.

The structural integrity of the building is unclear, Fire Superintendent Tim McConnell said. He praised firefighters at the scene and said the damage was as minimal as it could be.

Four businesses were destroyed in the fire.

The last six-alarm fire in New Orleans was in 2012, McConnell said.

Update, 8:45 a.m.: Five hours after the fire began, the New Orleans Fire Department continues to monitor the scene in the 1000 block of Canal Street.

The risk now is for collapse, Fire Superintendent Tim McConnell said at a news conference around 8:30 a.m. Firefighters cannot mount an interior attack in the building because of a cracked wall.

One firefighter sustained a burn to his hand and is being treated at a hospital, McConnell said. No other injuries have been reported.

McConnell said he expects NOFD to be on the scene at least 24 hours.

The building where the fire originated is owned by controversial t-shirt king Kishore "Mike" Motwani, according to Orleans Parish assessor records.

Over the years, Motwani has often tangled with city officials. A 2008 Times-Picayune story described him as "the man whom local preservationists, city regulators and even economic development gurus love to hate."

Among other reasons, the article citied Motwani's "repeated flouting of government regulations, his failure to maintain some of his buildings and his gobbling up of Canal Street properties to open cut-rate stores that impede efforts to upgrade Canal as a shopping destination."

The heavy smell of smoke blanketed the air for blocks around the scene of the blaze. Wind sent most of the smoke upriver from the fire, and many pedestrians could be seen covering their faces with scarves or coat collars.

Original story:

New Orleans firefighters are battling a large blaze Wednesday morning in the 1000 block of Canal Street between South Rampart Street and Roosevelt Way in the Central Business District, officials said.

There were no reports of injuries, Fire Department Superintendent Tim McConnell told WWL-TV. One person was inside the building when the fire began, but he was able to escape.

According to McConnell, the fire started on the second floor of the building. There is a cellphone company and beauty supply store on the first floor, but the building is unoccupied on other floors, WWL reported.

McConnell said the cause of the fire is still under investigation, but it is not believed to be suspicious.

The New Orleans Fire Department arrived at the scene at 3:26 a.m. to find a four-story commercial structure “fully involved,” NOFD said in a news release. The fire began to intensify around 3:40 a.m. Additional alarms were dispatched at 4 a.m. and 4:27 a.m. when the fire began to spread to neighboring businesses.

There is a "high probability" of the building's collapse, NOFD said.

As of 5:40 a.m., 31 NOFD units and more than 90 fire operations and support personnel were at the scene.

Canal Street will be blocked in both directions between Rampart and Burgundy streets until further notice. Buses have replaced the streetcars on Canal Street due to the fire, WWL reported.