In ster.com,
Pete C. typed:
Doug Miller wrote:

In article ,
Steve Barker wrote:
On 6/18/2010 8:58 PM, Some Guy wrote:
Is there any difference between a tank of welding oxygen
vs medical oxygen as far as purity, concentration,
hazardous impurities, etc, that would render welding
oxygen insufficient (or even dangerous) for helping to
supplement breathing / respiration ?

it's the same.

Ummm..... no, it's not. Read the other responses in this
thread from people who actually know the difference.

Yes, it's the same. Anything to the contrary is "urban
legend" or hype for the purpose of charging more for the
same stuff. All the O2 grades, including the five nines
analytical grade are filled from the same cryo tanks, and
only the analytical grade gets any extra testing to ensure
the 99.999% spec. The reality is that the welding O2 purity
standard (99.99%) is higher than the medical O2 purity
standard (99.95%), and that the actual product from the gas
suppliers exceeds those purity standards by a wide margin.

Amazing: All those posts, guesses and "sound good" types mostly, for a
question that's so easily answered with a search engine that it's actually
pathetic. This is precsely why groups like this have such low crediblity and
high drift rates.