I, for one, am a non-smoker.
It is not written in any operator's SOPs. It is something I was trained to do, some thirty years ago, as taking a professional attitude to the job and responsibilities. Safety first!
Of course, that was in the days when a Loadmaster was regarded as a professional crewmember and got rest periods like a human being
, unlike today when they are regarded as being a piece of the cargo equipment and only replaced when it breaks
