There are times one has to offer their credentials to validate their assertions.
I have a degree in Aviation Maintenance and hold a A&P (Airframe and PowerPlant).
Aviation Maintenance is among the most hazardous professions, mostly due to the substances we work with. In this profession (as well as many others) one learns there are long term consequences to chemical exposure. The effects of exposure to many substances is accumulative.
Because there are no apparent ill effects from exposure today does not mean there will be no ill effects tomorrow, next week, month, year or decade.
A breathable atmosphere is no guarantee of safety. I feel a breathable atmosphere is one of the greatest dangers. I lulls the breather into thinking there is no or little danger. Urethane based coatings with a catalyst are an excellent example. Everyone knows to get the hell away and upwind while Emron (i.e.) is being applied, they don't seem to know or care Emron (i.e.) gasses for up to several days. These gasses are breathable but in no way are they healthy.
I don't care to know what vapors turn into when raised to a high temperature or ran through a flame. I will not be exposed to them, or keep my exposure to a minimum if I have to be exposed.
I will note: I no longer work in The Industry. I had become sensitized to widely used substances. It's getting tempting to answer the fliers I get from contracting companies. I love the work but I don't want to get poisoned again.
Explosion hazard? A flash over is more excitement than I care to experience. It wouldn't have to raise the roof, blow out the windows or drop the building. Even if the odds are one in a million Why take a chance? My flesh isn't healthy enough as it is, but I think I want to keep it intact. Burnt or blown off is not an appetizing thought, least for me.
I've become extremely protective of my health. I'm 45. About ten years ago those things I did in my youth started catching up with me. Motorcycle mishaps. Exposure to chemicals. A couple slipped disks from an "encounter" with SWMBO in the shower. :]
If this is what it feels like to be 45 (especially my neck), I'm not into adding to what I've already done. It's going to happen, I'm going to get damaged again, I just know it. I'm not chasing it like I use to.