Harry Cash, better known as the Gas-Man, was a super-criminal who utilized a flying metal suit and a collection of special non-lethal "gases" to commit crimes and battle costumed heroes. Valuing above all else a chivalrous code of honour, shortly after serving a thirty-year prison sentence he befriended Gregory Dingham and enjoyed regaling him with anecdotes from super-history and teaching him the ins-and-outs of his code.
What Cash hid from Gregory, ultimately unsuccessfully, was that he had served those thirty years for the murder of his own wife. How much of what Cash had told Gregory is true or false is unknown.
Dingham and Cash broke into the Goodman Museum and stole back Cash's flying suit. Cash's behavior then became increasingly erratic, as he refused to take off the suit despite the incredible discomfort and heat and began mumbling nonsense. When the police caught up with the duo, and their hostage Katie Morgan (the second Dr. Metronome), Dingham summoned an earthquake.
Gravely injured in the quake, Cash spent his last hours alive rescuing survivors from the rubble.