ah, that reminds me of the old chemestry courses now. so the pure O2 environment that "caused" the old space capsule fire and the "no smoking" in areas where pure O2 is in use (back when you could smoke in hospitals) isnt because the oxygen burns on its own, but rather because it makes normal fires more likely and more dangerous.
a simple spark from an electrical outlet or lightswitch wont ignight the oxygen the way it would ignight a natural gas leak, but it is more likely to start an electrical fire which is more likely to spread.
right?
which leads to the question of wither you could smelt with bacon without pure O2 as the oxidizer. probably yes, if you started with a dung fire and fed it with powerfull billows. you'd think that the richest fuel would be pure lard, and isnt tallow essentially dried / refined lard? it was used in candles and lamps, but maybe it has larger applications? some googling suggests that there is some EU legislation going on about wither tallow burning is allowed in the waste incineration industry right now...
perhaps a good suggestion would be dwarf powered or machine powered billows, to aid in smelting. much like mills work. maybe some types of metals are unsmeltable without them, depending on their melting point. or maybe job speed changes... i think tallow-as-fuel has been brought up before.