George your experiment would not be a good test as the O2 would vent off, the O2 needs to be contained, like soaked in upholstery or trapped in layers of clothing . I was in the hazardous gas detection business for 40 years and am very aware of the risks associated with enriched O2. I was unfortunately called many times to help investigate cause/origin of industrial accidents, fires, explosions and confined space deaths. Fortunately enriched O2 is found in limited applications, medical, steel and a few chemical plants and is usually well controlled. The accidents like the link below are usually home bound people on O2 who still insist on smoking.
Years ago I saw a Mr Wizard type show where a lit cigarette was dropped into a beaker of O2, the cigarette was instantly consumed in flame. Enriched O2 will make things normally not flammable very flammable, does not have to be a hydrocarbon vapor, just something that can burn. But cotton, plastic, cigarettes are all hydrocarbons, just not vapors.
Now that I read the latest news report the OP talked about, it seems that some type of canister was the origin of the fire/explosion. While the information is limited, I am going to make the assumption that these folks were huffing and had a cigarette that set this stuff off.