I lost track of which thread it was in, but someone asked me if there was a CG regulation about storage of the small propane cans for grills on recreational watercraft. I asked my higher-ups and was told there was nothing official. But there are recommendations to not store propane cans below decks, in a cabin area or in an area where the propane could leak into an engine space. Propane is heavier than air and will sink to low spots.
2002 FV 342 on Lake St. Clair - Past Commodore SHC - Vessel Examiner USCGAUX