Are all copper cables virtually oxygen free?

I've been talking to folks at Storm Products and Allied Wire and Cable about ac cables -- both distribute and custom build various wires and cables. According to them, newer techniques among American manufacturers virtually eliminate any oxygen in copper. They could not speak to other manufacturers since "not a lot of wire is imported" -- presumably because of the cost dynamics. That means that, for all practical purposes, Romex has similar OFC characteristics to all the cables that are being touted. Of course, there are other sonic characteristics like crystal size (ala Harmonic Tech)and other non-copper impurities. But, is OFC a fait accompli for all cable? What does that mean? I'm way out of my range of expertise here but was wondering if anyone else has heard this and/or knows the implications. Thanks.
Short answer: Yes. But what's called "oxygen-free" is a little more oxygen-free than the regular stuff (assuming the label is honest). There is no technical reason why that extra purity should make a difference (though there's a lot of mumbo-jumbo from the people who sell it). Indeed, I've read (though cannot confirm) that OFC actually is more resistant than generic copper, which would make it an odd choice.
Let me add another question, Ozfly. Is there really any audible difference between 99.9999% (4 nines) and say 99.999999% (6 nines) purity copper? Just curious. Happy Tunes!
Parrot: If I'm not mistaken, 4 nines means 99.99%, and 6 nines means 99.9999%. Your question is still a good one, however.
Bomarc's answer is correct until he gets to the purity part of it and purity does make a measureable difference, but for lower resistance....Yes you can hear it as well....
All copper cables become oxygen free when they stop breathing. Hooking them up to a cable burner helps speed up this process as it effectively "electrocutes" them. For reasons of being politically correct and due to having too many threats from the ACLU, we've all agreed to refer to this as "cable cooking" or "cable burning" rather than "cable electrocution" or "conductor killing". Hope this helps clear things up : ) Sean
LOL, Sean... A breath-taking clarification of the complex conducting process!

Some are QF 9.9999999(Quality Free)too!The factor is listen to music,not cable.

I will give you another theory why cables sound differently.(I know this does not really answer the question, if all copper cables are virtually oxygen free, but I think the main reason behind this question was to find out, if impurities make a sonic difference in copper audio cables)According to Dr. Strassner, the founder of HMS audio cables ,it is not so much the amount of oxygen which degrades the sound in copper cables, but the amount of so-called ferro magnetic particles. According to him, he is one of the very few cable companies (probably the only one) who have their wire material checked for the amount of ferro magnetic particles, since this test is very expensive. He will reject any copper raw material with more than 6 ppm of ferro magnatic particles.
The ferro magnetic particles will align and re-align according the phase of the current and use up energy. And energy loss in a auduio cable always translates into sonic loss of the sound quality.
That is one reason why sometimes audiophiles cannot agree on the sonic performance of the same cable brand. Well, now it easy to see why.
If the manufacturer does not care and does not know the amount of ferro magnetic particles, one batch of copper wire can be fine and another batch bought month later, used to manufacture the same brand of cables, can have a far too high level and thus the cables made from this inferior copper raw material will be of lower sonical quality of course.
So if I may summarize, the only good cable is a dead cable. By definition, they are all oxygen free ;-)

Seriously, it does appear that the OFC dynamic may not be real critical. However, the other imperfections are a problem. Tekunda mentions ferro magnetic particles. Any other issues?

Famaraca, you are absolutely correct -- listening is the best test. I like to put things within context though and would like some general info that allows me to make quicker choices about things in the future to narrow down the options. Personal approach. I appreciate all the comments. Please keep 'em coming.