Seven homes that were under construction in Mount Albert have been destroyed following a large fire early Tuesday morning.

Fire crews were called to the housing development, located at Ninth Line and King Street East around 4 a.m.

Investigators say the fire is not suspicious; the Ontario Fire Marshal is now trying to determine the cause. However, fire officials say the homes were being heated with portable heaters and there are several propane tanks around the site.

“They put heaters in the basement, so they're running them on propane to keep them from freezing,” says construction worker Warren Stork. “They're big propane heaters, so they have big propane tanks in the back that feed them and they run all night" 

Investigators say the fire started in one home and quickly spread to others. At this phase of construction, the homes are mainly plywood. The developer has begun to assess the damage with its insurance company and is also starting to let waiting homeowners known about the setback.

The homes were schedule to be finished in August and at this point there is no dollar value for the extent of damage.

The fire marshal will be back on scene on Wednesday and will continue to investigate the cause.