"Richard J Kinch" wrote in message
. ..
jay writes:

Are you saying that even an oil lubricated compressor is safe to
breathe @ 1 bar (sea level).

Yes, in proper working order. That's my opinion and my firsthand
experience. It must be cleaner than the sidewalk of a busy city street
breathing exhaust, diesel particulates, etc.

Same here.

A couple of other things I have seen is coolers and charcoal filters.
Cooling the air prior to filtering will help wring out oil and especially
moisture. A floating dive shop I used to frequent actually piped the air
down 15' and returned it through an insulated line just prior to filtering.
The results were exceptional. The same could be done with a home-made heat
exchanger. The charcoal filter will eliminate any taste or odor problems, if
ever necessary.

You might visit some local dive shops, especially if you can find one using
a self made compressing set-up. Most will be glad to share their experiences
with compressing breathing air over the years.