Not a fire, but I updated Catalyst drivers while mining.  I wasn't paying attention and noticed after a few minutes, "Hey, my fan sure is quie....oh crap!".  My GPU was up to 105c.  MSI Afterburner was unresponsive to changing fan settings.  I stopped my miner and rebooted and all was well again.  I'll admit I did panic a bit.  Luckily the card is still rock solid for me.