Bruce in Bangkok wrote:

Winston, ships have been using flue gas to provide an inert atmosphere
in their tanks for years. Here are a couple of references:
First a long, rather drawn out discussion about ships:
http://www.spectacle.org/196/gross.html

Flue gas has almost no CO (70 - 160 ppm) It is a mixture of about
94% nitrogen and carbon dioxide and a little oxygen.

http://www.habmigern2003.info/19_flue-gas-contents.html

I think we can agree that flue gas, popularly used to displace air in
the fuel tanks of ships is non-flammable.

Can we also agree that that the carbon monoxide (CO) component of
exhaust gas as emitted from the tailpipes of most pre-1975 cars is
both poisonous and flammable?

Thassall I was saying. Sorry to ruffle ya.

--Winston