Investigators are working to determine the cause of a fire in the Old City section of Philadelphia Sunday.
Flames erupted on the fourth floor of an apartment building at 9th and Spruce Streets just before 9 p.m.

Firefighters were able to contain the fire to one apartment. No injuries were reported. There is no word on how many were displaced by the blaze.

It always happens when you think it's going to be a quiet night. At about 8:45, we got the call for an apartment fire. When we arrived, there was heavy black smoke from the roof area of a four-story row building. Many of these old houses have been turned into apartments.

This fire was in the worst possible place; in the rear of the fourth floor. It was in the walls and the roof. My crew did an excellent job of getting a 35- foot ladder in place, as well as a near-impossible main ladder shot directly to the roof.

In the video, you see a glimpse of my rookie John working with a saw on the roof cutting away hot spots. It was precarious up there due to the heavy smoke conditions and pitched roof next to us, but we were able to keep the fire contained to the rear apartment.

Ironically, the first in engine officer reported "Nothing Showing," because the smoke was so thick and black that it was difficult to realize what you were looking at. The smell was all we needed to know that something was up. All in all, a good job by everyone there.