OMG!!!! Glad everyone is ok. That's very scary.

Getting technical here: a lot of the synthetic fibres used to make carpet catch fire easily. In the 90's there was a new "wonder carpet" that they had to take off the market because vaccuum cleaners were melting the carpet, in a few cases setting the floor on fire! (please don't ask me HOW vaccuum cleaners were melting the yarns... I don't remember, all I do know is that my interior design teacher told us to stay far away from carpets made from that nylon fibre) Sounds like the manufacturer of the cat tree got hold of this carpet to make these cat trees.