If JW411 thinks that just because he flies a freighter aircraft, cabin pressurisation can be ignored, he is in for a very big surprise.
Supplemental oxygen is there for the flight crew to use IF normal pressurisation is lost or in the event of smoke/fumes and definately NOT to be used for long periods at high altitudes. For that you NEED proper pressure breathing equipment, and crew supplemental oxygen....ain't it.
To think otherwise may well result in a quick trip to the cemetary, never mind the hospital.
Beware...sometimes young guys are misinformed, as in big time
