FIRE! But under the dash, not the hood? Pics

[ppritchard]

Area to the left of the glovebox, looks like a finned metal piece -- that is the area where the fire was. Smoke started coming from the vents, then I saw the flames. Glovebox was out of the car, so you could see the flames to the left. Plastics were what was burning/melting.

What could have caused the fire?
Any idea what that finned piece is? Could it be the source.

Car had only been running maybe 5 min, so must have been electrical or something similar. Only recent work was a new ac compressor. No smoke under the hood, just here and through the vents.