i was wondering if it’s safe to breathe the oxygen tanks you find in hardware stores. the reason i ask is that when you see stores that sell oxygen cylinders for medical supply companies, they dont come filled and they always say you can fill them for $5. i’m assuming that for such a cheap price, it has to be the same place that would fill tanks that would be used in welding.
aside from that, let’s say they are safe to breathe. what health problems would i see besides nausea, passing out, and pneumonia?