Petrol, handled properly, is actually pretty safe.
Yes, it's the petrol fumes that are particularly explosive. Which is pretty much how a combustion engine works, with a large surface area for the oxidisation of the fuel (very small droplets of fuel = large surface area) producing a lot of heat which expands the gaseous (non-oxygen) content of the explosion (ignition) chamber, thereby generating movement.
In simple terms, the larger the surface area of the fuel as it burns the more of it is that is burnt in a given time frame and therefore the more efficient the engine. Petrol is not particularly explosive (otherwise it would be a very bad fuel for general use) and it strikes a rather useful balance between being burnable but without "help" is not burnable in a run-away form, as in an explosion. A party trick that I would not advise: pour petrol into a (relatively narrow and non-deep) container, light a match and extinguish it in the petrol. There should be a small flash as the petrol gas that forms over the liquid is burned but as long as the container is not too deep nor not left too long this is very short and the match will be extinguished in the petrol. Do not try this. Certainly not at your own home.