I am a veterinarian. The last time I went to my supplier for medical oxygen, only industrial oxygen was available. What is the difference between the two products? Does industrial oxygen have harmful contaminants? I have heard that it is sometimes recommended for emergency use in Third World countries.

"There is practically no difference between industrial and medical oxygen," said Ravi K. Bansal, chief executive of the Airsep Corp. of Buffalo, which produces both kinds.
The two come from the same source and are produced the same way, he said, but to sell oxygen as medical gas, as with any prescription drug, regulations must be complied with to ensure that it is being properly dispensed and that it is traceable, with a lot number in the event of a recall.
"It needs to be tracked, and sometimes tested if it is repackaged, as it moves along the distribution channel," Bansal said.
Industrial oxygen contains no harmful contaminants, he said, and is separated from air by a process in which air, collected in its gaseous form, is liquefied at very cold temperatures.
The different constituent gases boil off at different temperatures, making it possible to capture pure oxygen.
--NYT News Service