Firefighters spent hours on the scene of an overnight fire that ripped through CTV Ottawa's newsroom and caused more than $2.5 million in damage.

Flames began on the second floor of the Merivale Road building sometime before 4:30 Sunday morning.

It took 70 firefighters and 18 fire trucks more than two hours to bring the blaze under control.

"Crews did an excellent job holding it," said District Fire Chief Jim Corrigan.

"We managed to contain the fire to the second-storey of the building. However, smoke migration made it to the fifth floor."

Corrigan says $2.5 million is a preliminary estimate. Damage could be much higher due to the building's expensive content.

An overnight security guard was working when the blaze broke out. He suffered no injuries and no other injuries have been reported. The cause of the fire is unknown.

An ongoing investigation means it could be days before staff can return. However, plans to continue production from the A Channel building in the Byward Market are moving forward.

"Our management team had put in place a very comprehensive plan to deal with emergencies like this," said CTV Ottawa's General Manager Louis Douville. "They are things we prepare for but hope will never happen."

Building still standing

One reporter was notified when a friend called and said flames were shooting from the building and "crews were rushing to the scene."

"I knew it must have been bad because he kept saying he was sorry and that the building had burned down," said reporter Stefan Keyes. "I only live a four-minute drive away so I got dressed and headed out."

Keyes says when he arrived at the scene dozens of firefighters were there and paramedics were standing by. Broken windows revealed the newsroom was charred.

"Damages looked bad but the building is still standing. Thank God."

A stretch of Merivale Road in front of the building was closed for seven hours.

The newsroom hosts several workstations for reporters, producers, editorial staff and video editors. It means several computers, televisions, phones and personal belongings would have been destroyed in the fire.

Among the devastating property losses are the local news archives of this city's history and the 37-year video history of anchor Max Keeping who is set to retire on April 1.