On just about every DIY forum I've ever been on, there have always been discussions on the safety of using flammable solvents indoors.

While it's always better to be safe than sorry, it's also true that the risk of solvent vapour explosions is most often over estimated rather than under estimated.

The reason is that the air is mostly nitrogen. There's only about 22 percent oxygen in the air, and so it doesn't take much change in the oxygen level to have an effect on us. Typically, even when the vapour content in the air is well below 1 percent, say at 10 to 50 thousand parts per million, people start getting dizzy, get sore throats, start to vomit and eventually pass out well before the lower explosion limit is reached.

And, on the other side of the coin, 78 percent of the air is nitrogen, which is non-flammable. So, getting a fume explosion in air is much like setting fire to a pile of garbage where 78 percent of the garbage is non-flammable. So much of the energy that solvent vapours release when they burns ends up going to heat all the nitrogen in the air that you have to have a LOT of solvent vapours in the air to keep the combustion going.

Not trying to fan the flames here, (no pun intended) just trying to keep things real. You're far more likely to puke from inhaling too much solvent vapours than you are to blow yourself up.

Better to open up a window on each side of the house or space you're working in to get a bit of a breeze in the room, and to go outside for some fresh air whenever you find you're day dreaming a bit too much.