Ever heard of anyone blowing up a gas station by leaving their car running?

Went out with a friend and she had to stop and get gas. When she filled up the tank, she left the car running! Being a law-abiding citizen without a death wish, I couldn’t believe it! All these years, I’ve been conditioned to turn off the car, even in the dead of winter, by those huge signs that say, “TURN OFF THE CAR, YOU IDIOT. DO YOU WANT TO BLOW UP THE PLACE?” Okay, I exaggerate, but the signs are there telling you to turn off your ignition.

My friend dismissed me with a wave of her hand when I brought this up. “Have you ever heard of someone blowing up a gas station by leaving their car running? Besides, you START the car, don’t you? I’d think THAT would create more of a spark than letting it run the whole time.”

So, has anyone ever heard of someone inadvertently blowing up a gas station by leaving their cars running? Or are we all just being duped?

Hopefully this is not an urban legend, but I think I once read a news story about a car that caught on fire because the guy overfilled the tank, the gas ran under his car, which was then ignited by the car’s hot undercarriage. (Apparently, it was a low-riding sportscar.) I don’t recall if it was running or not.

Perhaps it’s just a “better safe than sorry” warning.

Funny, I was pondering something similar the other night. As I was getting my tank filled, I watched the two gas station attendants light up their cigarettes, ironically as they stood behind a “No Smoking” sign.

No one blew up, and I would think a lit cigarette is worse than a running engine.

I also seem to recall someone telling me that to prove a point, he saw a guy douse a lit cigarette with gas from the hose! At the time I believed him, but I’m thinking:

  1. Who does this for the first time “Gee, I wonder what happens when I pour gas on a lit cigarette”

  2. Pouring gas on the ground must make an awful mess.

I’m inclined to put this story in the UL category.

To answer your question, no. I’ve also never heard of anything bad happening anywhere when people don’t follow the relatively new warning to keep their gas container on the ground with the nozzle touching at all times, to avoid some mysterious static electricity that will turn your entire city to rubble.

But I guess when you’re dealing with as flammable a substance as gasoline (including its fumes), this would probably fall in the “better safe than sorry” category.

I wonder: Any old-timers know if, back in the '40s and '50s, when everybody thought smoking was OK, did they stub out those butts at the gas pumps? (Guess somebody would have been pumping your gas for you back then, but still.)

We in the Upper Midwest would happily accept some gas prices from that era immejitly.

While not the brightest move in the world it can be done. I have seen someone snuff a match in gasoline.

The trick is fumes. Gasoline by itself cannot burn. It needs oxygen (air) to ignite and burn. Problem is you usually get fumes very quickly from gasoline so as you approach the gasoline with a fire source the fumes just evaporated from the gasoline ignite.

Don’t try this at home though…chances are good that things will go FOOM in your face.

A good ice-breaker at fire safety lectures is to take the lid off a jar of petrol and immediately drop a lighted match into it, where upon it is extinguished instantly. The reason being that the it’s only the vapour that burns, not the liquid. Even then, the vapour concentration must be at about 7% for ignition to occur. This explains why the cigarette was doused without causing a fire or explosion.


To answer your first question, gasoline vapor burns, not liquid gasoline. I assume that the liquid cools too quickly as it transitions to the vapor state. Of course, I wasn’t a physics major; maybe someone else can explain it better. In any case, there’s not enough vapor around the cigarette.

Regarding question #2, I don’t know. It would make a mess. Maybe the demonstration was done decades ago, when no one cared about these things. I know that my dad used to talk about a demonstration where a match was put out in a pan of either gas in a breeze to show that it was the vapor that burned, not the liquid (it might have been diesel, but I doubt it, since he told me while talking about gas vapors.) FWIW, this demonstration was probably done between 1945 and 1970 and might have been part of a class or an in-shop fatory presentation.

FWIW, while I’ve never heard of anyone causing a fire by leaving their vehicle running at the pump, NPR stated that they’re asking people in Colorado to limit their off-road driving to prevent forest fires. I’m pretty sure that gasoline vapor is at least as flammable as grass, and catalytic converters get pretty hot.

Gee, There’s nothing like watching the replies stack up as you’re proofreading yours…

I can shed a little light (no pun intended) on this subject. I had a friend who was a cab driver in NJ. For those of you who don’t know, there are only full service stations in New Jersey with a few extremely rare situations. Anyway, in his cab and personal car (I rode with him several times) he would leave the engine on while the attendants pumped the gas. If there was an issue about it I am sure the attendants would have told him to turn it off even though they were “dumb gas jockeys.” He has been doing this type of thing for many years. I even asked him about it since I had heard the same story before and he said it was all bunk and that he gets his engine fuller that way. Personally, I think his explanation is bunk too, but he had a decent explanation of why it gets more full. He said that it put the gas more into the engine rather than just the tank and he could thus get the few hundredths (my interpretation as I don’t think it will add anything significant) of a gallon more gas into his car.

Also, for a while my father was a mechanic. He had five kids so he had to take that as his second job. His first being with the military. Anyway, the few times I ever went to the mechanic’s shop, they had a big open pail of gas in the corner. They would all smoke and throw their lit cigarettes into the can. This freaked me out to no end, as you can imagine. Anyway, if you throw a lit object into the gas and it gets completely submerged it will extinguish it and not blow everything up. It is not an intuitive process because I thought gas was much more flammable than that. I was wrong.


WOW, four people posted when I was replying to this thread. Interesting.


PunditLisa, the idea is prevention, so it never happens, thats the idea. I suppose you wonder about those NO SMOKING signs near the pump too?

I have never heard of anything blowing up from not turning off your car. As others have pointed out, your car is running when you pull in and you start it up to leave. Also, nothing stops other cars from pulling up to the pump while yours is filling. I do not think the concern is explosion. When I worked pumping gas the owner told me the policy is to minimize the exhaust build up so the pump jockey does not pass out (an exaggeration). This sounds more plausible than the explosion angle.

Gasoline is extremely flammable and it is mostly good luck that there are not more accidents.

I knew a guy who was having his motorbike tank filled while he sat on the bike. The attendant wasn’t paying attention and it overflowed and ignited (not sure how, maybe when it touched the hot engine). My friend was seriously burned and was left with an irrational fear of fire. He would panic if he thought there was any chance a fire might get out of hand.

I have not heard any cases involving cars while refueling but I have seen a few cars that burnt. I have heard many cases of fires and explosions involving boats, I guess because spills are much more common and also because the vapors have a chance to accumulate inside.

What seems pretty dumb to me is the attitude of people who disregard warning signs. Does it have to happen to you before you learn the lesson?

About a year ago there was a fire in the house two doors down from mine and an old man almost died. The space heater was being used in a manner that contradicted every warning that comes with it.

Of course, gas stations do explode. We had a case about six months ago here in Denver. A guy was driving down Wadsworth Blvd. when his car caught on fire. Of course, he would need to get his car fixed. So he drove it to the nearest service station. Which just happened to be a gas station. He rolled into the lot in his burning car and I’m sure you can get what happened next. It left quite a hole in the ground, since the underground tanks ignited, but I believe the guy was actually OK. And they repaired the station pretty quickly, too.

Maybe the reason no one has ever heard of a gas station blowing up because someone left their car running is. . .(drumroll). . . Most people obey the posted signs!!! Seriously, if most people obey the signs then there really wouldn’t be a big enough test group to figure out how likely this happens, right? So far, we only have sqrlcub who saw it done “several times”, plus the original poster. That’s really not a lot of trials. I bet if we had a day where no one turned off their engines while pumping gas, THEN we could statistacally examine the topic.

I thought that the issue was to guarantee that the car wouldn’t move away with the nozzle still in the gas tank.

"Maybe the reason no one has ever heard of a gas station blowing up because someone left their car running is. . .(drumroll). . . Most people obey the posted signs!!! "
I do not think this is the case. When I worked pumping gas there were numerous cars per day that would not turn off the engine. And that is only counting the ones that did it on my shift. If this is typical, then there would be a large sample size to indicate that it is not dangerous to leave the car running. Surely if it were so dangerous then the gas station owners would ask you to turn your engine off well away from the pump and push your car closer to fill it, then push it away to start it up before you leave. Obviously this is not the case.


I find it hard to believe that a gas station would blow up because of leaving the engine running. I also find it difficult to believe that a motorcycle would catch on fire because of gas on the engine. since I ride motorcycles all the time I’ve spilled enough gas on my hot engine and it’s NEVER caught on fire. I also see a number of MC guys that leave their engines running while they fill up. plus most of the truckers leave the engines running as they fill up.

The only things that I can really believe is too much exaust or possibly somesort of back pressure from the tank and throwing gas all over the place.

The boss always told us to keep the smoking inside (it was still cool to smoke in those days).

But people constantly were tossing butts, and dumping hot ashtrays out and starting fires in the trash cans.

Gasoline itself is quite able to jump minor gaps, as jump up a dripstream from a nozzle, unlike fuel oil, for example.

We had spillovers every week, usually some guy who likes to “top off”, then leaves the car parked in the sun at a slight incline while he’s in the adjacent diner.
Of course, the gas expands and overflows.

We did have employees who would light the pool to “get rid of it”, but that always brought crowds out of the diner.

I suspect though, if a pool ignited beneath your car and didn’t quiclky go out, there would be no one left to tell how the explosion started.

Another idea is that if the engine is running, then no one is sitting in the drivers seat. Not exactly the sort of thing you want at your station.

I would guess this has more to do with insurance and lawyers than practical flammability.