If you find out, let me know!
I have a TERRIBLE phobia of house fires. It used to be a very broad phobia, but over time, working with myself, I have sort of figured it out.
I sort of have it narrowed down to WHERE the fear came from, and I can only think of three things: A.) An episode of Rescue 911 when I was about 5 in which a little baby got trapped in her burning room. B.) The sight of a burnt house around the same time. C.) When my elementary school gym burned after an electrical fire, coincidentally, around the same time.
Knowing WHERE it came from helped me realize that I am not insane!
From there, I realized that what I am MOST fearful of is NOT so much a burning house, but the aftermath - a burnt house. It smells very bad, everything is ruined, and it takes a LONG time to make things right again, and even then, things are lost and nothing is ever the same. I probably know this because of my elementary school fire.
A few years ago, a house across the street from a friend had a BAD fire. It took everything I had, but I made myself look at and smell the house for a while. My heart was pounding and I was sweating and my chest tightened, but in the end, nothing happened.
I have pretty much beat that part of my phobia, and I can look at a burnt house, but if I see one on TV before bed, I have a really hard time sleeping, and I have to make sure all of the electric/gas things are turned off. That part of my phobia is more like an OCD, I guess.
Anyways, FWIW, I hope it can help you.