The main culprit here is the plastic-based filling found in couches, chairs and beds. The New York Times writes:
With more plastic in homes, residential fires are now likely to use up all the oxygen in a room before they consume all flammable materials. The resulting smoky, oxygen-deprived fires appear to be going out. But they are actually waiting for an inrush of fresh air, which can come as firefighters cut through roofs and break windows.
As long as there are no flames, firefighters prioritise search and rescue. But because of all of the plastic materials inside homes, a smouldering fire can rapidly catch again when firefighters burst in.
Now the Fire Department of New York is considering reversing its general protocol. So instead of rushing in to a smokey building, they might start hosing it down before entering. The department will be experimenting with a series of test fires by filling 20 vacant row houses with old plastic furniture from hotels and setting the buildings ablaze to see if a new approach might make a difference.
The new tactics might make sense, but you have to admit that it's pretty depressing that the mass-produced furniture that's supposed to make our lives better is actually making us harder to rescue from a fire. [NYT via Core77]