A lit cigarette is incapable of igniting gas or its vapours, the danger comes from igniting the cigarette.

Realistically, what are the odds of something going wrong unless you light up a cig while peeking right inside the fuel tank? Last year I've been taking smoke breaks at the gas stations every week near the pump with the crew working there, because I had to attend stuff in the middle of bumfuck nowhere, and wait around for potentially up to an hour with the gas station being the only inhabited place around. Still living and breathing, and I honestly don't see how it could've turn badly. Yeah, I know, vapors and stuff, yadda-yadda, but those can only be in high enough concentrations to be dangerous maybe, at worst, within a hand's reach of a tank or a nozzle? Otherwise, the station would have much worse problems than smokers.

Pretty sure all of that is fake news. It depends on deez.