I needed to use a medical oxygen concentrator for a short period, and I found it strange that it came with a warning label I was supposed to put in the window so firefighters would know it was there. I don't understand why firefighters would care. I would understand why they'd care if I used oxygen tanks; as they could add oxygen to a fire. But an oxygen concentrator doesn't add any extra oxygen, it just moves it. The same amount of O2 would be in the room either way.
Is there something about oxygen concentrators that's extremely flammable? Or is this more of a legal issue where they're just being overly cautious?
I apologize if this is the wrong SE.