Except, a lit cigarette can ignite a pool of gasoline. All those videos with stupid people holding cigarettes and igniting vapours at the gas station are proof

Except, a lit cigarette can ignite a pool of gasoline. All those videos with stupid people holding cigarettes and igniting vapours at the gas station are proof that gasoline can be ignited with a cigarette. What you need is for the cigarette to have enough time in contact with right concentration of vapours (2% to 8% by volume). Too little but also too much and you will not get it ignited. Here is a handy table listing necessary concentrations: https://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html https://www.engineeringtoolbox.com/explosive-concentration-l... Now, if you just drop the cigarette into a bucket of gasoline it will not ignite. This is because on a typical small pool/bucket of gasoline the layer with the right concentration of vapours is very thin and the cigarette does not fly long enough through it to ignite it before it reaches the surface and gets completely doused. There is couple of ways this can be prevented, the easiest is if you let the cigarette lay close to the pool of gasoline but not exactly within it. Drop it on the part of ground that only has very little gasoline on it so that the cigarette will not immediately get doused with it and can lay there waiting for the right concentration of vapours to happen. Bonus points if part of the cigarette get damp with gasoline. Another way is if the ground is hot and there is a lot of vapours. Or if there is very little wind. Or if the pool is somehow enclosed so that a fairly thick layer of vapour can form before it gets blown.