Subject: Can a gas (oxygen), at atmospheric pressure, enter a pressurized container?

Is it possible for O2 to enter a sealed pressurized gas pipeline at several 
hundred psig through osmosis or a chemical exchange from a small leak (from 
atmospheric INTO several hundred psig)?  Concern is with internal corrosion of 
a natural gas pipeline.  O2 is present, but is it being generated within the 
pipeline or is it "leaking in".  This question seems like one of those "Does 
water run uphill" types to me.

Re: Can a gas (oxygen), at atmospheric pressure, enter a pressurized container?