This from Eric Haak:
Just before 4:00 p.m. on Wednesday (7/27), the Village of Bedford Park had a fire at the Midway Windows and Doors warehouse. It looked as if there was an exterior fire that burned through the exterior metal clad wall and ignited interior stock and shelving. It also appeared that the exterior fire was being fueled possibly by some type of petroleum product. Foam was used to eventually extinguish the exterior fire which flared up several times. It is hard to see in the images, but the initial fire must have been very intense as it appeared that the fire was hot enough to cause the metal sheeting to fail which allowed fire to enter the structure. This is all speculation based on what I witnessed and should not be taken as information that was confirmed.