The Fairmont Chateau Laurier was partially evacuated Tuesday morning after a fire on the mezzanine level. (CBC)

Ottawa's historic Fairmount Chateau Laurier hotel is cleaning up after a small fire that caused an estimated $250,000 in damage.

No one was injured, but guests were forced to flee the first three floors of the historic building on Rideau Street just after 7:45 a.m. The blaze also caused major traffic disruptions for commuters.

Three floors of hotel had to be evacuated when smoke from the fire, which officials said was caused by a food heating tray set up for breakfast in an executive boardroom, reached the mezzanine level.

"The fire was pretty much knocked down by the sprinkler system once it was activated," said fire department spokesman Marc Messier. "[But] the sprinkler system will continue on until we shut it off, so there's quite a bit of water damage."

Natalie Kenny of Fredericton, N.B., said she was in the basement when she heard the alarm.

"People had come out and said there was smoke and smell," she said. "Little kids came out in the pajamas. For them, I think, it was pretty scary."

By the time the 32 firefighters and paramedics arrived on the scene, the fire had been extinguished, said hotel spokeswoman Deneen Perrin. She credited the hotel's alarm system for pinpointing the site of the fire and one of the hotel's engineers for grabbing a fire extinguisher and putting out the flames before they could spread.

The mezzanine level as well as the first floor above and the lobby floor below were evacuated as a precaution.

The fire and response caused traffic delays on Wellington Street and Elgin Street as police rerouted westbound traffic on Wellington just as the morning rush hour hit.

Ottawa police reopened Wellington Street at about 9 a.m.

With files from Omar Dabaghi-Pacheco