I'm not so sure the oil burners are scrutinized/regulated as much as wood has become? I'm thinking not, since I don't think I've heard of EPA clamping down on oil burners.
So I'd say either new ones being sold are meeting EPA regs (or else they wouldn't be allowed to be sold) - or there are no regs to meet, per se. That's furnace oil - I have no idea on the waste oil stuff. But there's kind of catch-22 in there with those too I think - if they're not tuned decently & burning 'right', they likely won't burn for long. Very tempramental, from what I've heard. Sorta like a mis-tuned 2-stroke fouling plugs.
Likely typical oil burner emissions could be googled up, and compared somehow to the EPA limits on wood burners, if one was so inclined.