Nitrogen O2 mix for pushing and purging?

I recently acquired a couple of cylinders of calibration gas (about 10# tanks) from a defunct pulp mill lab. I intend to convert them to CGA 320 valves for CO2 tanks (currently CGA 680?) they are certified to contain no more than 2% oxygen and the remainder nitrogen. Would this be suitable for pushing beer around, purging and sealing kegs maybe even serving wine? Don't really want to vent the gas off if it can be used.. save on CO2 for these chores as well.. then convert the cylinders when empty.

If there's O2 in there (2% would be roughly 25% of atmospheric O2) it's not advisable to push beer with it...

Cheers!