Scuba Tank for On Board air... stupid qestion?

[w squared]

A couple of disadvantages with CO2 is that it has a high rate of expansion when subject to temperature.
Also here in Aus any more than the equivalent of 2lb of Dry Ice / compressed CO2 is classed as dangerous goods & cannot be carried inside a vehicle & must be carried on an open tray. This is due to a leak from the bottle or the gas given off from the dry ice may cause asphyxiation to the occupants

TDG regulations are a very good point. I don't think that they apply to CO2 here in Canada in the quantities that we're talking about.

You may also want to check into whether or not those regulations apply to private vehicles that are not engaged in commerce. I know that in Canada, TDG marking regulations don't apply to private vehicles (otherwise we'd have to tag our Jerry cans with approved UN1203 tags).

You might have to tag a SCUBA cylinder with UN1002 tags as well - I guess it depends on your local TDG regs.

 

[1Engine]

Our dangerous goods laws apply to private vehicles over here.
We have had a few lp gas bottles explode etc over the years,.
They don't pull you over & carry out inspections however if you are involved in an accident & someone is seriously injured & it does not need to be in you vehicle then all the vehicles are impounded until a complete inspection is carried out by the police- thats when you get hung out to dry.
Scuba Tanks with air/ helox or trimix in them are OK, as the contents will "sustain life" as the contents are not heavier than air