Remove odd shadow
 

I have this pipe with a cellular material baked into its' appearance. During a script, the view point moves through the tube (like someone walking inside a pipe). However when I load the object there is this weird shadow I can't make disappear (see attached).

I've tried disabling/enabling viz.LIGHTING, adding lights along the inside. I am looking for a way, if possible, to not see any shadow inside the pipe.