There are probably still a few of the old cans around.  The new ones say
right on the can that it is CO2.  http://www.wd40.com/Brands/wd40_faqs.html
has a lot of info on the contents of the can.  Note also that there is NO
SILICONE in WD-40 either.

Mike Snow

>
> Michael,
>
> Really ?
> No propane in the WD-40?
> I wonder what is exploding in my potato cannon, to throw that potato 1/4
> of a mile.
>
> I don't think it's carbon dioxide.
>
>             ______________
>            |[  ] [  ] [ ]\
>            |    |    |    |
>      ~~~ ~||-(())----(())-|
>
> Terry--
> 74 Campmobile- (Clementine)
> 85 GL- (Delilah)
> 86 BMW 325 ES- (Eva)