A 74-year-old grandmother is clinging to life after a fire and explosion swept through her home in Ottawa's south end Monday night.

The fire broke out at about 5:30 Monday afternoon in a row house on Marlin Private in the Hunt Club Road and Bank Street area.

Sabah Abdul Hussein, who relies on oxygen tanks to help her breathe, was trapped inside the home's kitchen when the fire broke out.

Hussein has 16 children.

One of her sons, Zouheir Abdul Hussein, lives just across the road.

He said Tuesday he tried frantically to get to his unconscious mother out of the burning building.

"I tried to get inside, but as soon as I got to the second step the explosion happened, and it threw me out … The neighbours held me and didn't let me go inside, and I didn't hear her voice after. The fire department came a few seconds after, and I told them she is in the kitchen and they went inside and they grabbed her," Hussein said.

Hussein remains in hospital in critical condition.

So far, investigators haven't determined the cause of the blaze.

Hussein and a neighbour were treated for minor injuries at the scene, paramedics said.

One firefighter was taken to hospital with a knee injury.

Damage to the house was estimated at $100,000.