I bet they are, Dawg. Sure hope no one has been hurt!
Wonder if old window fans strung together with extension cords have had anything to do with the fires. This is on my mind because I have that exact rig in the girls' room right now!!
The fans themselves need to be maintained... big thing is keep any dust out of them so the motors can stay cool... older ones can be oiled but the newer plastic ones you just have to toss when they need oil

Extension cords can be a problem... especially if they're really "lamp cords" (the flat ones with outlets on the end for 3 more plugs)

You should buy and use heavier extension cords than you really need...
and don't put them under a rug or anything else that will hold the heat in (or become fuel for a fire)!!!
I'll look for a guide on extension cord use...