Originally Posted by mauer_62
just my $0.02 but the disposible oxygen bottles are intended for welding purposes only. citizens of the us cannot purchase pure o2 since it is a controled substance.(unless you steal it from grandma). you never know what is in those bottles that can enter your beer.
It's not a controlled substance per se, but rather it requires a prescription because when used medically for inhalation in a patient, a large enough amount can be fatal. See the following quote from Yahoo Health on this https://answers.yahoo.com/question/i...6033442AA6Jbyt
Welding oxygen, if inhaled can be just as fatal in the wrong amount, but it's not intended for inhalation and is just not certified to as stringent a standard of purity as medical oxygen when filled at a welding shop, for example. Medical oxygen also requires a completely different regulator. It is controlled in the sense that they require a prescription, but they usually are filled from the same equipment, albeit the medical oxygen tanks are treated a little better than the welding tanks and the person filling them has to follow a more strict set of procedures in order to maintain said certification.