CO2 purity

[Woolsocks]

I decided to ask what tests were done on our purchased CO2 by the supplier. He assured me they had rigorous tests to make sure it was food grade, but he wasn't sure what sort of oxygen content it had. He gave me a sheet they get from their supplier (an ethanol plant I think) which lists things like moisture content, etc. as well as something called "Purity (Zahm Nagel)", which was 99.99%

Who knows what they're testing here? I'm guessing that that means I have upto .01% non-CO2 gas in it?