When you were disconnecting from power had you already turned the tanks off ?
Was the tank nearly empty ? Some times on a nearly empty tank you can get a big whiff of the tracer gas that's added to LP so you can smell it.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.