The question came up a couple of weeks ago about what kind of gasses are
given off when a VW aluminum/magnesium engine burns.  I said I would check my
resources at my firestation and get back to the list.  Well, I finally got
the answer.

The main properties that are burning, Aluminum and Magnesium, give off mainly
Hydrogen and Nitrogen (I'll get back to how Hydrogen affects things later).
 They also give off particles of Aluminum and Magnesium in a microscopic size
(which can be lethal in itself if inhaled).  In addition, the burning of
fluids accessories and rubber give off various gasses that are generally bad
for humans.  The carpeting (should it catch fire) gives off, among other
things, Phosgene.  Now, how does all this affect us (and fire-fighters)?

Well, because Hydrogen is flammable and Magnesium burns at such a fast rate,
the temperature of the fire is higher than most engine fires.  Also, since
Magnesium is a burning metal, it is not easily put out by water.  A special
chemical is needed to extinquish burning metals.  So, just by the nature of
the engine, they are difficult to extinquish.  

Other factors:  The bumpers on later model Vans have shocks that absorb
impact in accidents (as do most modern cars).  Approaching a van directly
from the rear is not a safe way to extinquish a fire.  If the shocks that are
behind the bumper explode, they will propell the bumper with enough force to
break legs.

Also, Phosgene gas is extremely poisenous.  In a slightly different
concentration, it is used as a chemical agent in chemical warefare.  (VERY
bad stuff)  This Phosgene, by the way, is one of the reasons why a smoke
filled room in a house is so deadly.

So, not only are they hard to extinquish, they are dangerous to approach and
potentially deadly to be near.

Gregg Carlen,  Burke Volunteer Fire & Rescue Department, Burke, VA
85 Westy (144k)
76 Goldwing
51 Plymouth
75 Mercedes
69 Alcort
...need more toys!