When is somebody gonna talk about the dangerous flammability of oxygen?
Oxygen is not flammable, but it does intensify the combustion process and can cause fire to burn hotter and faster. It does not act as fuel for the fire to burn, it does however act as the oxidizing part of the fire triangle.
https://firefighterinsider.com/is-oxygen-o2-flammable-actually-no/O2 makes burning things burn much faster and hotter. Ever blow onto embers trying to make a campfire or wood stove catch? Same idea.
Many years ago, one of my first jobs was delivering medical gas to various places such as hospitals, dentist offices, and home care. Filled up countless liquid O2 containers too. When we filled the liquid O2, we had to vent the pure gaseous O2 from the tank. Pure O2 works wonders on hangovers...so I've been told.
The machines people plug in for 02 are called "Concentrators". The premise is the machine brings in air from the atmosphere and forces it through a sieve bed (fancy filter). The O2 is separated and concentrated and it goes to the patient. The excess gases are vented out. No oxygen is produced. These machines worked great for people using 2 liters or less. The machine had efficiency of mor than 98% O2. The machine loses efficiency as the rate of delivery goes up. I'm sure the newer machines are more efficient.
Some of the patients had issues with the O2 causing their nose to dry out. The last thing you want to use for relief is petroleum jelly. The petroleum and pure O2 can be a dangerous combination. Make sure to use the humidifier on whatever O2 delivery system you use.
If you go the concentrator route, get a backup of O2 tanks. E size made from aluminum. They won't go bad and shouldn't leak. Talk to your utility company and if they know you have it hopefully you'll be a priority if an outage occurs. The E tanks can sometime be used on flights. However, many airlines will require you to use their systems and won't allow your tanks. Make sure you contact them before you fly.
Liquid is ok, but needs refilling regularly. The tank is essentially a big thermos bottle. Even if you fill it and don't use the O2, the unit will gradually vent off the gaseous O2 as the liquid turns to gas. You can also get portable units to fill from your main tank for outside the house. A big plus is it doesn't use electricity.
The big tanks are a pain. The upside is they rarely leak. The tanks are heavy and awkward. You can't fill the tanks yourself. Changing the gauges can be tedious.
Ended up quitting that job for various reasons. One of the primary reasons was it got too hard to pick up equipment from the houses of people who passed away. Another was many of these people were very lonely and I was the only one they saw on a regular basis and I just couldn't keep my route current and spend time to chat.
Good luck