I own a 1912 Edwardian in San Francisco. I am in the process of putting in a new light fixture in my hallway. When I took down the old fixture, there was a 4" pipe coming down through the middle of the box, which will be in the way of the base of the new fixture. Here is a picture:
http://dc-loomis.com/photos/hallway-light.jpg
Someone told me that this might be pipe for an old gas fixture, but I kind of doubt it becuase there are electrical conduits coming into it now, but I thought it's better to be safe than sorry. Is this pipe safe to remove? If so, any idea how it comes out? The screw with the green arrow goes into wood. The screws with the red arrows attach the box to the pipe, but do not allow the box to be removed.