the reason propane is considered a bit more dangerous than natural gas is
that it does not float away... it can and has found low spots to lurk in
waiting for an ignition source... It is not nitro but it does deserves your
respect and undivided attention when you are working with it... My dad sold
the stuff ... when I was a kid I worked with it and service equipment that
used it... I did not lose any body parts but I did lose some hair and made a
number of hasty exits...

The Europeans refill similar small bottles at their version of superwalmart
and have for years... it is a swap out situation... one refills bottles by
weight ... someone must weigh a full bottle and an empty and get the proper
charge weight... then the refiller must have a scale accurate at this lower
charge weight level .. seems a lot to do for 3 bucks but it is recycling I
guess...