One thing to watch out for with propane is that it's heavier than air
and "pools" at low places.  For outside leaks that's not terrible
(unless you're in a low spot), but it could potentially build up
until it hits an ignition source.

Boaters know this since propane can go into the bilge.  Thus there
are many safeguards on boats (timed cut-off valves, etc).  Others now
use compressed natural gas (CNG) which is lighter than air.

-Karl
Karl and Kristina Bloss, Trexlertown, PA
'87 GL Weekender  "Beverley"
VW shop list: http://www.enter.net/~bloss/vw/vwshops