I'm sure the guy either had COPD or lung cancer and was trying to quit smoking. I used to work in the DME industry. We supplied oxygen concentrators, liquid o2 systems and bottled o2 to people in their homes. It would floor you if you knew how many people smoked while on o2.
I worked hospice for 11 years and the majority of patients were smokers with COPD/lung cancer. And oh yeah they did. With trembling hands and falling, still burning butts and ashes, and constantly. Somehow in all of those years there wasn't a single incident, something about the way the tanks were sealed, I was told. "Could happen but a very long shot." None of the long-time medical staff were really very concerned about it, just a token warning and let it be, though they'd not admit that to oversight. The patients didn't care at all, by and large - smoking was a last consolation and kind of a way of shaking a defiant fist at the universe, there was no stopping it.
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