Daniel J. Stern wrote:

>
> The stuff sold as air dusters is often R134a, ...

It really gets me that it's illegal (in the U.S., at least) to vent R134
from a car's A/C system but there's no problem with venting it from those
'air' dusters and other products in which it's used as a propellant. From
what I understand, you can't buy R134 at all in Canada without a license
but those dusters. etc. that use it are OK for anyone to buy & use.