A fire that ripped through a Nepean row house complex Sunday began on the balcony of one of the units, and could have been caused by a discarded cigarette, according to the Office of the Fire Marshall.

The fire damaged 32 residential units in four buildings at 32, 34, 36 and 38 Northview Rd. — 31 that were occupied and one that was vacant — displacing some 75 people from their homes.

"At this juncture I can say with certainty that the fire did not originate within the structure itself," said Office of the Fire Marshall investigator William Hay, who said a balcony at 34 Northview Rd. is clearly where the fire began.

Hay said "smoking materials" such as cigarettes is one of the sources of ignition investigators are looking into. He said so far he's seen no evidence to suggest any foul play, though they are still investigating.

The first emergency calls came in at 12:29 p.m., with reports of flames and black smoke coming from the roof of the complex on Northview Road. The second alarm was declared at 12:34 p.m., a third alarm at 12:41 p.m and a fourth alarm at 2:14 p.m., according to Ottawa Fire Services.

Witnesses said high winds contributed to the spread of the flames. Environment Canada recorded wind gusts approaching 30 km/h around the time of the fire.

Ottawa fire Chief Gerry Pingitore said the blaze was very heavy at times when firefighters arrived on scene.

One person was injured and treated on scene, according to Pingitore.

Fire could have been much worse

An emergency centre was set up at a nearby apartment building at 30 Eleanor Dr. for displaced residents. The Salvation Army and the Red Cross were helping those people to find temporary housing.

Fire investigator William Hay and Ottawa fire Chief Gerry Pingitore speak outside of the Northview complex a day after a four-alarm ripped through the buildings. (Radio-Canada) "It is pretty devastating ... families essentially, that had their world turned upside down," said Ottawa Fire Services spokesperson Danielle Cardinal Monday.

Cardinal said while there was significant structural damage to the buildings, the fire could have been much worse.

"I'm very fortunate that I'm not reporting fatalities this morning," she said

Residents had to leave quickly

One resident of 32 Northview Rd. said he thought the fire alarm he heard was just a drill until someone started banging on his door.

We … ran outside and it was just a huge wall of smoke. - Resident of 32 Northview Rd.

"We grabbed a jacket and everything and ran outside and it was just a huge wall of smoke. And huge flames coming out of the middle building there," the man said.

He said the firefighters were quick to arrive at the scene and tackle the blaze that seemed to be spreading due to high winds.

"Luckily, my unit's fine, but there's a lot of people that, like, that entire top floor is completely out. It really sucks. I'm feeling empathetic because I know what I was feeling watching the fire move over towards my unit and hoping they got it under control and stopped it.

"I can only imagine what it's like to be standing here and watching your unit, your home, up in flames."

Damage had been estimated at $3 million to $3.5 million.