This actually happened to me...kinda. It wasn't a fire, but we got a MAJOR flood a few years ago. I'd say 70% of my collection was safe in my room at the time, but the rest were in the basement which got a foot of water. All of the CDs were intact and are playable, but there was damage to the CD casings, covers, and info cards/booklets.
From the flood damage, all of the CD casings were thrown out. I'd say maybe a little over half of the covers/info cards were salvageable while the others were either molding or stuck to the casing or other parts of the pamphlet. I had to dispose of them and was more determined to get them replaced until I saw what some of the soundtracks were going for nowadays. I was like "screw that", I'll keep what I got.
Another good thing was that I was in the process of moving and the day the flood happened, we were going to see a series of houses, but postponed the visits for two days due to the rain. Once we were able to house shop again, the realtor said that if any house we visit has flood damage, they would not be considered. The main house I wanted to look at didn't see a drop of water; I eventually made the deal and am living there to this day. And those soundtracks are NOT in the basement