Many people know about the Hindenburg fire at Lakehurst and why static electricity combined with the use of Hydrogen as a lifting gas is bad news, but most people forget that there were a lot of other accidents where the use of Hydrogen was either the cause of the accident or resulted in fatalities or injuries, when none would have resulted if non flammable Helium had been used. The fatalities in the R101 accident that occured mostly because of low flying, bad weather, lack of sufficient test flights and serious overloading, were the direct result of a post crash Hydrogen fire. The R101 disaster resulted in similar bad press articles to the last flight of the Hindenburg, but the R38 accident is in some ways more interesting in technical terms and for more information on that accident see: http://en.wikipedia.org/wiki/R38_class_airship (Operational history) Picture: The R101 on mast at Cardington.
LIST OF PREVIOUS HYDROGEN AIRSHIP ACCIDENTS
There is an excellent list of past disasters from Hydrogen use on the following web site page and it will give you a very clear understanding, that using Hydrogen for any type of manned airship is very dangerous, even when the airship is on the ground or in a hangar: