Steven Magee said this quote

When I worked on the 13,796 feet very high altitude summit of Mauna Kea we were advised to only use the medical oxygen after the daily headaches appeared and that just 15 minutes use was all that was needed to clear up the headaches for a while before we would need it again. We were not advised to use medical oxygen continuously as the Federal Aviation Regulations advises pilots to do. We were not advised to use pulse oximeters to monitor our blood oxygen levels or that the company medical oxygen should have been routinely administered only with our doctors prescription.