My thoughts are with the injured guys. Here at Big Airways we charge O2 bottles in situ on the aircraft although there are very stringent rules about the process. In days gone by our instrument guys did it because it was thought they were less likely to introduce grease into the process - but now - almost anyone can do it and I'm sure it is only a matter of time before we have an incident. When it happens I quess one of the stringent rules will have been broken and I know who will be considered to be at fault and it won't be the company.
As an aside - what problems are encountered transporting charged cylinders? Does this present an equal risk?