An investigation is underway into an overnight fire at an apartment complex in northeast London.

The fire broke out at 11:30 p.m. Monday in a first floor unit at 75 Oakville Ave. just west of Clarke Road off of Huron Street.

Extensive damage could be seen inside the unit, which faces Pawnee Park.

The outer bricks of the building were burned from the first floor window of the unit all the way to the third flood.

A fire inspector was expected to begin an investigation Tuesday.

No one was injured in the fire and a cause has not been determined.

Another fire Tuesday sent a 24-year-old man to hospital in critical condition.

Fire officials say two men were attempting to start a fire in a pit on Cairn Street in the southeast of the city. Dry wood was placed in a pot and gasoline poured onto it.

The fire became out of control and the man was covered with gasoline and vapours, severely burning him. The second man was not injured.

Fire officials warn never to use accelerants such as gasoline on an open burn. They say open burns in fire pits must only use clean, dry wood.

Open burning is also prohibited under the following conditions:

  • wind speed exceeds 15 kilometres per hour
  • it is rainy or foggy
  • a smog day has been declared.

- With files from Kathy Rumleski, CTV London