DENVER (CBS4) – Two people escaped from an apartment that caught fire after an explosion Thursday morning in Denver’s Lowry neighborhood.

Witnesses said they suspect a heat lamp on a porch may be to blame for the fire, which happened in the Lowry Heights Apartments complex on East 12th near Ulster.

Firefighters were able to stop the fire from spreading to other buildings.

The Red Cross said initial estimates are that 18 units were evacuated and six units were damaged by fire.