If you can, get Air Tested to Grade E NFPA 1500... and please note that SCBA air, (firemen's breathing packs) is normally pumped by a mid-range compressor (3000-6000 psig) going through several stages of purification, into a "cascade" of several DOT Cylinders, then the 30 minute cylinder is fed off the cascade.
With proper Purification, even a standard 5-10 hp shop compressor can be used to produce breathing air... It is recommended the the compressor is operated using "food grade" oil, and system should have a CO monitor... Air samples should be to a certified lab at least every 3 months.
You've all seen the link
www.uapc.com any questions, call us.