A phone charger, plugged into an extension cord, on the sofa. Accidentally gets covered over with a blanket and end result is a fire. My question is: Can a phone charger get that hot to ignite a blanket? How is that possible? Could the sofa be the ignition source? Aren't those things treated with flame retardant? Just from being covered? It is not like a laptop computer that needs the vents clear. I realize this is way more that one question. Sorry.