As the flames intensify, the smoke and hot air rising off the fire are more than 190 degrees F. Heat from the fire radiates to other parts of the kitchen, heating up tables, chairs, shelves, and cookbooks.
The hot cloud of smoke thickens and deepens below the ceiling. Cyanide and carbon monoxide levels steadily increase: at 3,400 parts-per-million (typical levels in enclosed room fires) survival time is cut to less than one minute. Carbon monoxide poisoning causes more fire related deaths than any other toxic product of combustion.
When the smoky layer inches down to the top part of a doorway, an open window or a vent, it quickly streams out of the room. Then the poisonous smoke and heated air travels through hallways and up stairwells to the second floor.