The fire damage shown here was caused by an electric clothes dryer at a WI home. (There is a gas hookup but the owner was using the 240 volt electric supply for the electric dryer.) The dryer vent was plastic and went up through an interior wall and terminated in the attic, it did not terminate on the exterior of the house as it should have. The fire apparently was caused by overheating which was likely caused by a clogged exhaust vent. The person living there was having an outdoor party and was doing laundry when the fire started. 13 roof trusses had to be replaced in the attic.
All clothes dryer vents should be solid metal and terminate on the exterior of the house. These exhaust ducts should be checked for lint build up every year. The Consumer Product Safety Commission reports that there were 15,600 fires associated with clothes dryers in 1998 (the most recent year for which data are available), accounting for about 20 deaths, 370 injuries, and more than $75.4 million in property damage.